I see Sans from Undertale, Jack Skellington from The Nightmare Before Christmas, The Wither from Minecraft, Skeletron from Terraria, Lord Hater from Wander Over Yonder, Skeletor from He-Man, Sir Daniel from MediEvil, and that's all I can name.

I know Skeletron and Sans :D

And the Wither and Nightmare before Christmas too :P