Looking for a particular unofficial costume thread? Then here's an all-inclusive list of links to each one that I've created!
IN GAME:
Ant-Man
Black Cat
Black Panther
Black Widow
Blade
Cable
Captain America
Captain Marvel
Colossus
Cyclops
Daredevil
Deadpool
Doctor Doom
Doctor Strange
Elektra
Emma Frost
Gambit
Ghost Rider
Green Goblin
Hawkeye
Hulk
Human Torch
Iceman
Invisible Woman
Iron Fist
Iron Man
Jean Grey
Juggernaut
Kitty Pryde
Loki
Luke Cage
Magik
Magneto
Moon Knight
Mr Fantastic
Nightcrawler
Nova
Psylocke
Punisher
Rocket Raccoon
Rogue
Scarlet Witch
She-Hulk
Silver Surfer
Spider-Man
Squirrel Girl
Star-Lord
Storm
Taskmaster
Thing
Thor
Ultron
Venom
Vision
War Machine
Winter Soldier
Wolverine
X-23