These two songs have the same key

Otonoke x Kekka Orai (Dandadan x My Hero Academia: Vigilantes Mashup)

HIGH FLAME (Tsuyobi) x Mephisto (Fire Force S3 x Oshi no Ko Mashup)

APT. x Monitoring (DECO*27 x ROSÉ, Bruno Mars Mashup)

ReawakeR x Nox Lux (Re:Zero S3 x Solo Leveling S2 Mashup)

ReawakeR x Abyss (Solo Leveling S2 x Kaiju No. 8 Mashup + AMV)

2024 Animash (120+ Anime Songs Mashup!)

Otonoke, but it's a Christmas song

Otonoke x Kizuna No Kiseki (Dandadan x Demon Slayer Mashup)

POP IN 2 x Shikairo Days (Oshi no Ko x My Deer Friend Nokotan Mashup)

Otonoke x Shikairo Days (Dandadan x My Deer Friend Nokotan Mashup)

Racing Into The Night x Monotone (YOASOBI Mashup)

These two songs have the same key

Katachi x September (Made in Abyss x Earth, Wind, and Fire Mashup)

Hai Yorokonde x Battle Hymn of the Soul

Shikanoko goes well with any anime song (My Deer Friend Nokotan Medley)

Fatal by GEMN x Black Bullet (Mashup of Oshi no Ko Season 2 x Black Bullet)

UNDEAD by YOASOBI x 99.9 (Monogatari Series: Off & Monster Season x Mob Psycho II)

Rickroll Megamix (April Fools 2024)

Bling Bang Bang Born x Rivers in the Desert (Mashle Season 2 x Persona 5 Royal)

2023 Animash (130+ Anime Songs Mashup!)

Lost in Paradise x More than Words (JJK Season 1 x Season 2 ED)

Idol by YOASOBI Remix Mashup (Oshi no Ko OP)

Drown x Amadeus (Vinland Saga x Steins;Gate Mashup)

Mephisto x My War (Oshi no Ko x Attack on Titan Mashup)

Wareta Ringo x Yesterday (Shinsekai Yori x Hello World Mashup)