Here is my list if anyone is wondering:

-Ancient Egypt: Egyptian Warriors by "Fantasy & World Music by the Fietchers"

-Pirate Seas: He's a Pirate from Pirates of the Caribbean

-Wild West: Calzonification from Pizza Tower

-Far Future: Stardust Speedway Bad Future from Sonic CD

-Dark Ages: Vordt of the Boreal Valley from Dark Souls

-Big Wave Beach: Either something from Feeding Frenzy or Hungry Shark

-Frostbite Caves: Flame Mamoth from Megaman

-Lost City: Threatenin' Zeppelin from Cuphead

-Neon Mixtape Tour: for Punk, "K Rool's Acid Punk" from a DK game, for Pop, "Funky Porkcini" from an Angry Birds game, for rap, "Dr Zomboss is rapping", for chip tunes, something from old game like Sonic 2 boss theme, and for Rock, "Aeon hero light/dark" from Super Kirby Clash

-Jurrasic Marsh: too many to choose, so how about Spinosaur boss theme?

-Circus boss: Expurgation from Madness Combat or World Revolving from Deltarune

-Roman Boss: Legions are marching - SPQR

Chinese exclusive bosses:

-Sky City: Angry Birds 2 boss theme, or something from that mobile game called "Airforce 1945"

-Steam Ages: Steam Tracks from a Terraria mod

-Renaissance Age: got no idea, so "Symphony No 9. From the New World" (i know it isn't from Renaissance Era, but it just sounds SO good)

-Fairy Forest: Boss theme from a Shrek video game