Even with only two games and a bonus edition, the NiGHTS series has being referenced in a lot of games and even in other types of media.
NiGHTS has made many cameos in the Sonic Series, appearing in Sonic games more than his own, NiGHTS is also the used as an inspiration for the creation of some Sonic Characters, such as the Chaos who were based on Nightopians and Black Doom who was based on Wizeman.
Sonic Adventure (1998)
There's a pinball table in Casinopolis which was inspired by NiGHTS with NiGHTS himself making a cameo, many other characters also appeared as cards, in the NiGHTS table, the player can collect all five Ideyas in the table and if they do, they'll be rewarded with 300 rings.  It’s also possible to make the chaos have their heads shaped after NiGHTS and Reala's hats by giving them flying animals, by giving Chaos power animals, it’ll make them look like Jackle, though the later might have been unintentional.
Sonic Shuffle (2000)
When playing the game on December 24, NiGHTS will make a cameo appearance replacing Lumina as the guide of the game, by playing the game in April 1, it'll be Reala.
Sonic Adventure 2 (2001)
NiGHTS made cameos on posters in the City Escape stage and in Radical Highway, NiGHTS has an Hotel named after him and once again, it's possible to make the Chaos look like NiGHTS and Reala by giving them flying animals and Jackle by giving them power animals.
Sonic Pinball Party (2003)
Every level from NiGHTS into Dreams, appeared as Pinball tables in Sonic Pinball Party, every table featured some of the enemies from the game as obstacles and a boss after beating the level, Elliot made a cameo on the Frozen Bell table, Claris on the Mystic Forest table and both on the Twin Seeds table. Sonic Pinball Party is the only game where NiGHTS actually interacts with Sonic, where he helped Sonic free Amy and Tails from Dr. Eggman hypnotism, NiGHTS is also a level two competitor in the Egg Cup tornament.
Sonic Pinball Party featured all of the major characters, bosses, enemies and levels from NiGHTS into Dreams.
Sonic Battle (2003)
In Sonic Battle, NiGHTS appears in the Speed Demon minigame, where they can be seen flying in the background.
Shadow the Hedgehog (2005)
In Shadow the Hedgehog, a Billboard of NiGHTS can be seen to the right of where Shadow begins Lethal Highway as soon as he lands on solid ground.
Sonic Riders Series
Sonic Riders (2006)
NiGHTS, along with AiAi and Ulala, is a SEGA guest character who makes an appearence in Sonic Riders as a playable character, He can be unlocked by completing all the Babylon's missions, NiGHTS Extreme Gear is called Night Sky, the Twin Seeds tower also appears in both SEGA Carnival and SEGA Illusion courses.
Sonic Riders: Zero Gravity (2008)
NiGHTS is the only SEGA guest character who returns to Sonic Riders Zero Gravity, this time, also featuring Amigo and Billy Hatcher, once again, NiGHTS can be unlocked by completing all of the Dr. Eggman's missions in the game, Night Sky also returns and this time, the Bellbrigde Clock tower appears in the ‘90s Boulevard circuit.
Sonic Generations 3DS (2011)
The same NiGHTS hotel from Radical Highway reappears in the same stage in Sonic Generations for the 3DS. Making NiGHTS the only non Sonic character to appear in Sonic Generations.
Sonic Lost World (2013)
There's a NiGHTS themed DLC zone called Nightmaren Zone in Sonic Lost World in the Nightmare Zone, where Sonic fights the Deadly Six riding NiGHTS into dreams bosses, the zone starts with Zazz, Zomom and Master Zik riding on Puffy, Wizeman's hand and Gulpo respectively, then Zeena, Zor and Zavok riding Clawz, Jackle and Gillwing respectively, Wizeman and Reala make a cameo at the beggining of the level where they'll turn the level black and white and Reala is responsable for transporting Sonic to Nightmare by paralooping him, at the end of the level, NiGHTS will appear and paraloop Reala, defeating him and bringing the colors back, the zone ends with Sonic saving Nightopians inside a NiGHTS capture.
The Nightmare Zone is the only DLC zone to return to the PC port of Sonic Lost World, the obvious reason is because it's the only DLC to not be based on a Nintendo property.
Sonic Runners (2015)
NiGHTS, Reala, Nightopian, Christmas NiGHTS, Christmas Nightopian and the Red Ideya appeared in Sonic Runners as Buddies for a limited time, when they are used the music will change, NiGHTS will give bonus points when characters pass though a loop, Reala will give the character magnet effect after a loop, Nightopian can randomly destroy spikes, iron balls and enemies when the character gets damage, Christmas NiGHTS can reduce the game’s speed, Christmas Nightopian can trigger the the Yellow Drill effect and the Red ideya switches na Equipped item for another.
Sonic Forces (2017)
An unlockable costume based on NiGHTS appears in Sonic Forces, other character's costumes that appear in the game are an AiAi costume, an Amitie costume, a Beat costume and a Joker's costume.
SEGA Superstars series
NiGHTS is a recurring series in the SEGA all star series.
SEGA SuperStars (2004)
In the party EyeToy game SEGA Superstars, there’s a NiGHTS into dreams minigame where the player controls NiGHTS by using their arms as if they were flying.
SEGA SuperStars Tennis (2008)
NiGHTS appears as a playable in the default roster, while Reala appears as an unlockable character, Aqua Garden also appears as an unlockable stage, featuring Sweeping Seashore (default music), The Amazing Water, She had long ears and Paternal Horns as music tracks.
NiGHTS Superstar move plays a small bit of the NiGHTS into dreams main theme and can make the other players teleport to far away from the ball, Reala Superstar move plays a small bit of NiGHTS and Reala theme and can make the player spin.
Sonic & SEGA All-Stars Racing (2010)
NiGHTS appears as a flagperson who waves the checkered flag at the start and end of races. Steve Lycett of Sumo Digital said that NiGHTS could potentially become a DLC character if the game became successful. However, later that year, Sega announced that they no longer planned to include any downloadable content after the release of MetalSonic and the Death Egg Zone track.
Sonic and All Star Racing Transformed (2012)
NiGHTS and Reala appeared as unlockable characters in Sonic and All Star Racing Transformed due to popular demand, both shapeshift themselfs into cars/boats/airplanes and they are driven by a Nightopian and a Goodle respectively, when NiGHTS goes all star, he shapeshifts back into his normal form and drill dashes into the racers with Message from Nightopia playing in the background, as for Reala, he also shapeshifts back to his normal form and shoots fireballs at the racers with a D'Force Master remix (Wizeman's boss theme) playing in the background.
The game also features Spring Valley as an unlockable circuit under the name “Dream Valley”, the circuit features rings which the racers can pass through to get boost and giant Shleeps, Kircles and Alarm Egg appear as obstacles, there's also a portal which teleports the players to nightmare, with the nightmare section changing every lap, in the first laps, it teleports to Gillwing's lair with Gillwing making a cameo, in the second lap, it teleports to Puffy's mansion with Puffy making a cameo and opening the way to the racers and in the last lap, it teleports to Wizeman's lair with Wizeman appearing as an obstacle, trying to slow down the racers by throwing meteors at them.
Additionally, Lynne Triplett, a very famous artist and NiGHTS fan among the NiGHTS Community worked in the game and drew the following NiGHTS, Jet Set Radio, Skies of Arcadia and Burning Rangers stickers, unfortunately, only the Jet Set Radio stickers were accepted for the game.
Burning Rangers (1998)
Chuchu Rocket! (1999)
In the Puzzle game for the Dreamcast, it's possible to replace the Chuchus with nightopians by completing all the 50 courses.
NiGHTS and a Nightopian appeared as capsule toys in Shenmue along with other SEGA characters. NiGHTS had two capsule toys in the game and the Nightopian toy comes with a Chao toy.
Samba de Amigo (2000)
Dreams Dreams is a song featured in the Dreamcast rhythm game, Samba de Amigo, the song didn't return the Wii port. 
Phantasy Star Online (2000)
NiGHTS made a small guest appearence in Phantasy Star Online I & II Plus, in an Episode 2 quest, the game also featured a NiGHTS into dreams minigame where the player controls NiGHTS in Spring Valley, there are no enemies nor dreamers in this mini game and when the time is up, the player gets a Night Over instantly. 
Segagaga, or SGGG, is a role-playing simulation video game developed by Sega Hitmaker and published by Sega for the Dreamcast and released only in Japan which tells the story of two young children who must help Sega beat it's main competitor, a company called DOGMA, that has taken 97% of the home console market, many Sega characters make a cameo through the game and NiGHTS is among them, other Sega characters that also make a cameo are Sonic, Ristar, Alis Landale and Alex Kidd.
Billy Hatcher and the Giant Egg (2003)
In the platform game Billy Hatcher and the Giant Egg for the Gamecube, there's a special type of egg called Sonic Team Egg, which summons characters from SEGA games to assist Billy in his adventure and NiGHTS is one of them,  the player can make NiGHTS drill dash into enemies all over the screen, other characters who make an appearance are Sonic, Tails and Knuckles from the Sonic series and Amigo from Samba de Amigo, there’s also a circus hat in the game that resembles NiGHTS purple jester hat and the minigame from Phantasy Star Online reappears in this game, additionally, the final boss from the game, Dark Raven, will shoot a dark orb at Billy during the second part of his boss battle, when Billy touches the orb to turn it into a light orb, the orb will turn into a white orb which looks very similar to the White Ideya.
Feel the Magic: XY/XX (2004)
NiGHTS hat is an unlockable costume for the girl in the mini game compilation video game Feel the Magic (Known as Kimi no Tame nara Shineru in Japan and Project Hub in Europe), the game also features a Sonic hat, a Chao hat, an Amitie hat and Ulala's pigtails as unlockable costumes for the same character. 
SEGA Splash Golf! (2008)Sega Splash! Golf is a free to play Japan exclusive game released for the PC, the game was announced in 2007 and released in 2008, it stars a boy named Rush and a girl named Miel who set out to become professional golfers.
The game features NiGHTS and many other SEGA characters such as Sonic, Tails, Ulala, Opa-Opa and Puyo Puyo as a supporting character.
Phantasy Star Portable 2 (2009)
A NiGHTS and a Nightopian costume are avaliable in the game.
Samurai & Dragons (2012)
Many other SEGA characters characters also appeared in the game as cards, such as Sonic characters, Beat, Ulala, AiAi, Akira Yuki, Ryo Hazuki, Bayonetta, Kazuma Kiryu, Sakura Shinguji and more. 
Phantasy Star Online 2 (2012)
NiGHTS makes a cameo as a statue in Phantasy Star Online 2, a free-to-play online action role-playing game which is the sequel of Phantasy Star Online, the game was originally released for the Windows only in Japan in 2012, later for the PS vita in 2013, for the Playstation 4 in 2014 and Nintendo Switch in 2018, in 2020 the game was finally released to the west but only for the Xbox ONE and Microsoft Windows.
Rhythm Thief & the Emperor's Treasure (2013)
Rhythm Thief & the Emperor's Treasure is a rhythm puzzle adventure video game developed by Xeen and published by SEGA for the Nintendo 3DS in 2013, one of the game's features is the "sounds" which are secrets that can be found through the game's overworlds, one of the sounds in particular is called "Merry-Go Round", which can be found by clicking in a merry go round in the Tuileries Garden, when this sound is found, it'll play a small bit of Merry Memory Go Round (Memory Forest chase theme) from NiGHTS: Journey of Dreams,  particarly, it's a bit at the end of the theme  other SEGA easter eggs featured in the game are a Space Channel 5 and a Samba de Amigo minigame.
Dengeki Bunko: Fighting Climax (2014)A 2D arcade fighting game developed by Ecole Software and French Bread and published by Sega which celebrates the 20th anniversary of ASCII Media Works' Dengeki Bunko imprint, featuring various characters from light novels published under the imprint such as characters from Toaru Majutsu no Index, Sword Art Online, and Mahouka Koukou no Rettousei.
Dengeki Bunko features many SEGA thematic stages and Bellbridge is among them, the game also features Green Hill Zone from the Sonic series, a Valkyria Chronicles stage, a Shinobi stage and a Virtua Fighters stage.
The game was first released in Japanese arcades in March 2014 and later in the same year on PlayStation 3 and PlayStation Vita, the console version was released in North America and Europe in October 2015.
Project X Zone 2 (2015)
Project X Zone 2 is a crossover tactical role-playing game for the Nintendo 3DS developed by Monolith Soft and published by Bandai Namco Entertainment. The game is a crossover between various franchises from Bandai Namco, Capcom, and Sega, with special guests from Nintendo, among the cast, there are Street Fighters characters, Sakura Wars characters, KOS-MOS from the Xenosaga, Phoenix Wright & Maya Fey from Ace Attorney, Ulala from Space Channel 5, Segata Sanshiro from the japanese advertisement for the Sega Saturn, Kazuma Kiryu from Yazuka and Chrom, Lucina and Tiki from the Fire Emblem series.
NiGHTS himself doesn't appear in the game, but If Segata Sanshiro is paired with Reiji and Xiaomu, Xiaomu will say “Dreams, Fun and Inspiration are the Engine of happiness!” and Segata will continue saying “And you can’t have dreams without NiGHTs! Sega Saturn!”  during their pre battle dialog, NiGHTS' name was incorrectly written with the "s" not being in caps, two other characters who also don't appear in the game but are referenced are Sonic and Tails.
NiGHTS has a few references outside of games.
Movies and TV
In the australian independent movie Paws, the main character has a NiGHTS and Reala poster in his room, the poster appears to be based on a magazine ad for NiGHTS.
Danny Phantom (2004)
NiGHTS most notable reference outside of games is in Nickelodeon animated series Danny Phantom, where Nocturn, a ghost with dreams related powers and the main antagonist of the episode Frightmare, wears a purple jester like hat which is clearly inspired by the NiGHTS' hat, Nocturn is the ghost of sleep and dreaming and his main power is the power to make people sleep, the more people are sleeping, the more powerful he gets. The episode was aired on August 2007, four months before the release of NiGHTS journey of dreams, after his debut episode, Nocturn never appeared in the show again until the show's last episode, Phantom Planet, though he has no major role and just makes some cameos in the background along with others villains from the show.
None of the show's writer ever confirmed if NiGHTS was one of the inspirations for the character's design, however, it's safe to asssume NiGHTS was, due to the coincidences, which are a similar hat, dream releated powers and NiGHTS: Journey of Dreams being in development at the time. The show also featured a villain inspired by the Terminator called Terminatra, a villain inspired by the Predator Alien called Femalien and a villain inspired by Freddy Krueger called Nightmerica, unlike Nocturn, these three villains were already confirmed to be inspired on the said characters, additionatly, the villain Freakshow has a weapon called Reality Gauntlet, which was inspired by the Infinity Gauntlet from the Avengers.
Nocturn was voiced by James Garrett, an actor who worked on Titanic and Time after Time and was the voice of Roku in Avatar: the Last Airbender.
Powerpuff Girls Z (2006)
Some fans believe that Mojo Mojo design in the Japanese Magical Girl anime series Powerpuff Girls Z is based on Wizeman, coincidently or not, Roger L. Jackson, the voice of Mojo Mojo, would later voice Wizeman in NiGHTS journey of dreams.
Durarara!! (2010)A NiGHTS easter egg can be spotted in the anime Durarara!! in the 22th episode from the first season, "Declaration of Dissolution", there's a moment where Celty and Shinra are seen playing video games and it's possible to spot NiGHTS into Dreams over the table among the games.
Mangas and Comic Books
Game Gag 1P Comic Sega-hen (1997)
In 1997, Gêmesuto Komikkusu released a japanese gag comic called Game Gag 1P Comic Sega-hen dedicated to SEGA games, among the games refered was NiGHTS, NiGHTS was featured in the pages 62, 67, 92, 93, 96 and 97. The characters that appeared were NiGHTS, Reala, Wizeman, Elliot, Claris, Puffy and Nightopians. NiGHTS, Reala and Puffy are also seen in the comic's cover.
Hyperdimension Neptunia: Megami Tsuushin (2010)
Various Sega characters appear in the manga series Hyperdimension Neptunia: Megami Tsuushin, including NiGHTS who was called "Mysterious Unidentified Flying Creature".
Worlds Unite (2015)See more about Worlds Unite here
NiGHTS, Reala and Wizeman appeared in the Archie Comic, Worlds Unite, a comic crossover between Sonic and Mega Man which would later feature NiGHTS and other SEGA and Capcom characters such as Alex Kidd, Ryu from Street Fighters, Vyse from Skies of Arcadia, Amaterasu from Okami, Viewtiful Joe and more.
The comic also featured Nightopia and the Dream Gate as location
SEGA Hard Girls
NiGHTS appers in the Japanese multimedia project SEGA Hard Girls. A project which re-imagines various Sega video game consoles as anthropomorphized goddesses who appear all over modern Japan.
Additionally, NiGHTS might have influenced the design of the character SEGA Saturn, Saturn's hair resembles NiGHTS hat and she a neck collar which resembles NiGHTS neck ruffle.
In 1994, Disney's Epcot resort opened a technology museum called Innovations with the purpose to showcase hi-tech entertainment such as video games, Disney made a partnership with Sega and the museum got a section dedicated to people to play Sega games such as Sonic games, Virtua Fighters, Toejam & Earl, Aladdin and more, in 1997, NiGHTS into Dreams was added to the attraction, later, the whole attraction was closed in 2001, very little information about the attraction exists and footage of it are extremely rare nowadays. 
Shigeru Miyamoto, the creator of Mario, Donkey Kong and The Legend of Zelda revealed himself to be a fan of the NiGHTS' series, in an interview back in the Dreamcast times, Yuji Naka once said that many fans including Miyamoto himself were curious to know if a new NiGHTS game was in development for the system. 
Additionally, there's also a famous Miyamoto quote known among the NiGHTS community, where he says "If there is a game I would have loved to work on, it would be Nights into Dreams…” 
Japanese Game Symphony
On their 14th concert in 2015, the Japanese Game Symphony permorfed SEGA games music, which included NiGHTS into dreams music,  the following tracks were featured:
- Fragmented Nights
- Gate of Your Dream
- Paternal Horn
- Gloom of The NHC
- Suburban Museum
- The Amazing Water
- Take The Snow Train
- Under Construction
- The Dragon Gave a Loud Scream
- She Had Long Ears
- Deep It Lies
- E-LE-KI Sparkle
- The Mantle
- NiGHTS and Reala
- Growing Wings
- D’Force Master
- Peaceful Moment
- NiGHTS, Forever in Our Heart
- Sowing Seeds
- Dreams Dreams
- Fragmented Nights: Epilogue Ver.
- Since the release of the first game in 1996, the NiGHTS series has been refered at least once per years from 1997 to 2015.
- Before all of the NiGHTS cameos in the Sonic games, it was Sonic who made a cameo in Christmas NiGHTS into Dreams, there's a mini game where the player can control Sonic through Spring Valley called Sonic the Hedgehog into Dreams, which features Eggman as a boss parodying Puffy, the mini game did not return in the HD remakes of the game. 
- Christmas NiGHTS into Dreams was also the first game to have Sonic playable in a 3D environment.
- Unlike pretty much, all of the NiGHTS into Dreams original characters, who made at least two appearances, (including main protagonists, antagonists, bosses and minions), none of the NiGHTS: Journey of Dreams original characters, besides Goodle, ever made a second appearance nor cameo in anything, not even in NiGHTS releated media, Goodle made a cameo in Sonic & All Star Racing Transformed driving Reala shapeshifted as the car.
- Despite that, NiGHTS, Reala, Wizeman and Nightopians have appeared in their NiGHTS: Journey of Dreams designs in all of their appearances since the game's release in 2007, with the only exceptions being in SEGA Splash Golf, the remakes of NiGHTS into Dreams and other games which NiGHTS appeared that were made before NiGHTS: Journey of Dreams.
- NiGHTS: Journey of Dreams original levels, such as Bellbridge and Aqua Garden made more than one appearance.
- Will and Helen were indirectly mentioned in the NiGHTS notification from Sonic Runners, though that can't be considered an appearance.
- All of NiGHTS' cameos in the background of Sonic Adventure 2's Radical Highway were removed and replaced with chao images in Mario and Sonic at the Olympic Winter Games, probably because the developers didn't want non Mario and Sonic characters appearing in the game.
- Big the Cat's theme from Sonic Adventure, Lazy Days, contains a guitar which sounds very similar to the one used in the Clawz battle theme from NiGHTS into Dreams, curiously both are cat characters.
- During the Sonic the Hedgehog 2020 movie trailer, there's a moment where many little screens showing SEGA games appear to form the SEGA logo, among them, there's a screen showing NiGHTS flying through Soft Museum which can be seen for a very brief moment.
- NiGHTS into dreams was a major influence for the creation of the game Rodea the Sky Soldier, a game also produced by Yuji Naka. 
- ↑ https://www.youtube.com/watch?v=KzCnSclRnnw
- ↑ https://www.youtube.com/watch?v=gswQ-Yemd88
- ↑ https://www.youtube.com/watch?v=DxBBMvTb5yE
- ↑ https://youtu.be/OcBlyAXuBic?t=173
- ↑ https://youtu.be/aImmPAM7Aq8?t=4805
- ↑ https://www.siliconera.com/2012/08/28/samurai-dragons-adds-sonic-bayonetta-phantasy-star-and-more-sega-all-stars/
- ↑ http://segabits.com/blog/2012/11/21/samurai-and-dragons-sega-all-stars-pack-revealed/
- ↑ https://s.inside-games.jp/article/img/2012/11/21/61590/324840.fullscreen.html
- ↑ https://youtu.be/qCq_ievBP9o?t=851
- ↑ https://youtu.be/riZHROjpfSI?t=105
- ↑ https://youtu.be/B01T-nehgOs?t=205
- ↑ https://www.youtube.com/watch?v=hU1HLeQfzkk
- ↑ http://info.sonicretro.org/Yuji_Naka_interview_by_Official_Dreamcast_Magazine_(September_1999)
- ↑ https://sixtyhertz.wordpress.com/2007/07/10/nights-vid-wii/
- ↑ http://www.tssznews.com/2015/05/02/symphonic-sega-concert-to-be-held-in-japan/
- ↑ https://www.youtube.com/watch?v=40xQHxylN9U
- ↑ https://www.denofgeek.com/us/games/rodea-the-sky-soldier/247389/rodea-the-sky-soldier-new-game-from-the-creator-of-sonic