A little bit of everything. It's easier to think of them in batches, with initial characters and everyone else spreading from them like a creative disease.

Dead Leon - Zombieland and Scott Pilgrim with a bit of Left 4 Dead
It's Permanent - Home Movies and Supernatural Barbarians - Wall of character tropes from college Tigs - Clowns in the woods of 2018 Becky and Blud - Max Fleischer era cartoons