I did not ask what their characters were, though the girl makes me think of Horo (probably not it, though).
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.
A flipped version of Teemo, a giant mushroom with a small furry beast.
Lelouch vi Britannia.
Nora Valkyrie.
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.
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.
Buttercup.
Mega Man.
Zero/Lelouch.
The Medic.
Yuno and Raven.
Johnny and Lisa.
The Heavy.
A quartet.
Jedi.
Two Survey Corps members.
Spawn.
Sona.