This is a list of anime crossover that I will be posting I will also post some of the theme songs that I posted from my fanfiction stories ideas. last I thought I sure post fanfic of songs crossover but I was too lazy so this year I'm doing it.
List
Kamen Riders
Heisei Riders
Kamen Rider Kuuga/Campione
Kamen Rider Kuuga!| Masayuki Tanaka
Kamen Rider Agito/GATE
Kamen Rider AGITO| Shoko Fujibayashi
Kamen Rider Ryuki/Fate Apocrypha
Alive A life| Rica Matsumoto
Kamen Rider Faiz/Kill la Kill
Sirius| Eir Aoi
Ambiguous| GARNiDELiA
Kamen Rider Blade/Akame Ga Kill
Skyreach| Amamiya Sora
Liar Mask| Rika Mayama
Kamen Rider Hibiki/Naruto
Re:member| FLOW
Kara no Kokoro| Anly
Kamen Rider Kabuto/Full Metal Panic
NEXT LEVEL| YU-KI
Kamen Rider Den-O/Assassination Classroom
CLIMAX JUMP| AAA
Kamen Rider Kiva/Vampire Knight
Futatsu no Kodou to Akai Tsumi| ON/OFF
Kamen Rider Decade
Journey Through the Decade| Gackt
White Ideal| Mashiro Ayano
V.I.P| SID
Eien Ni Hikare| TOMORROW X TOGETHER
Kamen Rider Double/RWBY
W Boiled Extreme| Aya Kamiki & TAKUYA
Kamen Rider OOO/Bleach
Anything Goes!| Maki Ohguro
Harukaze| Scandal
Kamen Rider Fourze/Hundred
Switch On!| Anna Tsuchiya
Bloodred| D-selection
Kamen Rider Wizard/Chivalry of the Fail Knight
Life is SHOW TIME| Sho Kiryuin
Kamen Rider Gaim/Infinite Stratos
JUST LIVE MORE| Gaim no Kaze
Kamen Rider Drive/Nisekoi
SURPRISE-DRIVE| Mitsuru Matsuoka EARNEST DRIVE
Kamen Rider Ghost/Fairy Tail
Warera Omou, Yue Ni Warera Ari| Kishidan
Kamen Rider Ex-Aid/Sword Art Online
EXCITE| Daichi Miura
Kamen Rider Build/Cross Ange
Be The One| PANDORA & Beverly
Kamen Rider Zi-O/Date A Live
Over "Quartzer"| Shuta Sueyoahi (AAA)/ISSA (DA PUMP)
I Swear| Sweet Arms
broKen NIGHT| AIMER
MORE THAN LiKE| BiSH
Reiwa Riders
Kamen Rider Zero One/My Hero Academia
REALXEYEZ| J/Takanori Nishikawa
Kamen Rider Saber/Danmachi
ALMIGHTY| Tokyo Ska Paradise/Yoohei Kawakami
Kamen Rider Revice/RWBY
Opening liveDevil| Da-Ice ft. Subaru Kimura
Kamen Rider Geats/Battle Game in 5 Second
Trust Last| Koda Kumi & Shonan no Kaze
Future Riders
Kamen Rider Shinobi/Senran Kagura
IZANAGI| Sakuramen/Hideye Tawada
Kamen Rider Quiz/Baka and Test
Perfect area Complete!| Aso Natsuko
Kamen Rider Kikai/Accel World
T.M Revolution| Preserved Roses x Nana Mizuki
Dimensional Riders
Kamen Rider Pirate/One Piece
Hope| Namie Amuro
Kamen Rider Houou/Absolute Duo
Absolute soul| Konomi Suzuki
Kamen Rider Electro/Dimension W
Genesis| STEREO DRIVE FOUNDATION
Kamen Rider Bahamur Undefeated Bahamut Chronicle
Hiryu no Kishi| True
Kamen Rider Saint/Saint Seiya
Pegasus Seiya| The Struts
Kamen Rider Destrus/World Break: Aria of Curse for a Holy Swordsman
Singularity| World Order
Kamen Rider Creator/Re:Creators
gravityWall| SawanoHiroyuki[nZk]:Tielle&Gemie
Kamen Rider Frozon/Re:Zero
Konomi Suzuki|Redo
Kamen Rider Shield/Rise of the Shield Hero
RISE| MADKID
OC Kamen Riders
Kamen Rider Mythical
Choir Jail| Konomi Suzuki
Kamen Rider Tune
Utaeba soko| Konomi Suzuki
Kamen Rider Unite
One Day Sky| Konomi Suzuki
Ultraman
Ultraman Cosmos
Spirit Goro Matsui
Ultraman Ginga
Legend of Galaxy ~ Hinga no Hasha| Takamiy with Mamoru Miyano
Eiyuu no Uta| Takamizawa Toshihiko/THE ALFEE
Ultraman X
Ultraman X (song)| Voyager/Kensuke Takahashi
Ultraman Orb
Orb no Inori| Ichiro Mizuki/Voyager
Ultraman Geed
GEED no Akashi| Tatsuomi Hamada/Voyager
Ultraman R/B
Hand| Masayoshi Oishi
Ultraman Taiga
Buddy, steady, go!| Takuma Terashima
Ultraman Z
Goshowa Kudasai Ware no Na wo!| Masaaki Endoh
Ultraman Trigger
Trigger| Takao Sakuma
Other Ultraman
Ultraman Mebius
Ultraman Mebius (song)| Project DMM/Ultra Guard
OC Ultraman
Ultraman Beyond - Core Fade| OLDCODEX
Super Sentai
Kishiryu Sentai Ryusoulger
Kishiryu Sentai Ryusoulger| Tomohiro Hatano
Mashin Sentai Kiramager
Kiramai Action| Psychic Lover
Kikai Sentai Zenkaiger
Zenryoku Zenkai! Zenkaiger| Takeshita Tauruno with Kotonomi Children Chorus
Avataro Sentai Donbrothers
Ore Koso Only One| Win Morisaki
Obsama Sentai King-Ohger
Zenyoku King| Takayuki Furukawa
Imagine Thought Idea Opening Fanfiction
Kamen Rider Zi-O/Date A Live
Brand-new World| Shiena Nishizawa
Kamen Rider Geats/Battle Game in 5 Seconds
No Continue| Akari Kito
Ending song
Kamen Rider Zi-O/Date A Live
Tsuki to Hanaba| Sayuri
this is all the songs see ya later