Rey.

Takumi from Fire Emblem.

Rocket Raccoon.

A nice Megatron dress.

Madoka Kaname.

A Cthulhu-themed outfit.

Roman Torchwick.

Mike, another friend, as a more generic trainer.

Team JNPR.

Ed and Luffy.

Black Cat.

Captain Komamura of Bleach.

Jolteon gijinka.

A maskless Deadpool with Domino.

A One-Punch Man quartet.

Yang Xiao Long.

Lelouch vi Britannia.

Shaggy and Scooby.

A female Deadpool.

Asuka Sohryu/Shikinami and Shinji Ikari.

Jade.

Satan Hercule.

Navi.

A Wreck-It Ralph trio.

Apollo Justice.

Star-Lord and Loki.

A HYDRA member and an original costume.

The Engineer.

Ruby Rose.

The Dude.

Nora Valkyrie.

A gentlemanly Deadpool.

Ditto.

Genos.

Presumably two ninjas.

A Tier 5 Priest from WoW. (Again, I apologize for blurry output.)

Team Rocket's Boss Giovanni. Another person challenged my Trainer friends on his behalf to a battle.

Kylo and Rey.

Joseph Joestar.

Post-apocalyptic Mario.

Mega Man.

Zero/Lelouch.

Johnny and Lisa.

The Heavy.

A quartet.

Jedi.

Two Survey Corps members.

Spawn.

Sona.

A Legend of Zelda trio.