Here's some of my ideas that from what I could find no one has made.
Chars:
-Neon White (from Neon White)
Features the card mechanic from that game
-Prop Hunt (from gmod)
Heavily based on the custom character by steam user loaf created for the game Rivals of Aether
(Heres the link for it if you're interested: Steam Workshop::PropHunt (steamcommunity.com) )
-V1 (from Ultrakill)
We have Gabriel, Minos Prime, & Sisyphus Prime
Why not also the main character from the game as well
Joryu (From Like A Dragon Gaiden)
It would just be a edit of Brergrsart's Kiryu Kazuma character with the mechanics of him from like a dragon gaiden: the man who erased his name
Stages:
-2 stages from the game Starbound (both of them are from the workshop for Rivals of Aether)
1. The Ark (Steam Workshop::Starbound - Ark (steamcommunity.com))
2. Escape the Earth (https://steamcommunity.com/sharedfiles/filedetails/?id=1963070370)
-A stage based on Neon White
-Air Armada (from Rivals of Aether)