Cuphead - @headspacekel
Mugman - @Da_Treino
Ms.Chalice - @Emmalar
Chef Saltbaker - @theSheepGod
King Dice - @LUNATIK93
The Devil - @Boris-The-Wolf-Bear-Official
Elder Kettle - @kuragari-sama

Random Secondary Characters:
Captain Brineybeard - @Not-Person
Ribby and Croaks - @Sel499 and @DaRealMemeCentralLol
Cala Maria - @Homicidal
Beppi The Clown - @Projektile
Djimmi The Great - @8bittinkywinkyIsSusGames
Cagney Carnation - @quandile
Goopy Le Grande - @QUANDALEDINGLEFANCLUBE
Werner Werman - @nelltounia_2
Mortimer Freeze - @tv_empire
Grim Matchstick - @losermeat
Sally Stageplay - @Elfsprout
The Root Pack - @MilkyOfficial
Phantom Express - @TBE-operative-fun
Hilda Berg - @K-nmaK-zume
Dr.Kahl - @VeryFamus
Glumstone the Giant - @ZaulBarraca
Baroness Von Bon Bon - @bunnybloodz
Wally Warbles - @Kholey69
Moonshine Mob - @ping_me_if_you_are_giga_chad
Esther Winchester - @Bean_Soup3
Rumor HoneyBottoms - @ELEANOR_THE_HEDGEHOG_dead
The Howling Aces - @YumiGaming_ @NoobGaming and @Joaoarthur_official
Angel and Demon - 2 versions of boris

Casino Bosses Characters:
Pip and Dot - @mechie and @CringeIdiotBreadFace
Tipsy Troops - @joe_biden7945 @somefnafluigimomentbruh
and @Lexxie
Mr.Wheezy - @SSO
Chips Bettigan - @Regalito
Mr.Chimes - @Undying3215
Hocus Pocus - @Oswald_64
Pirouletta - @Saphori
Mangosteen - @anthonylmao
Phear Lap - @cs888901

King's Leap Bosses Characters:
The King - @Xander2907
The Pawns - 8 random GameJolt users
The Knight - @OSWALD-PLUSHIE-GAMING
The Bishop - @WisdomTheFunkyBoi
The Rook - @Captain_Galaxy
The Queen - @Kemp_tilin88

That's all, I finally got them all