CC BY SHMUP Sprites

[Nikita_Sadkov]

http://ykkb.deviantart.com/gallery/48698975/Pixel-Art

Although I would recommend avoiding the anime characters, because they are non-free and appear to be coming from some copyrighted comics, called "Touhou Project".

The artist has some original free characters, which should be safe:
http://ykkb.deviantart.com/art/Necroman ... 7378&qo=38
http://ykkb.deviantart.com/art/Sorceress-443135601

I love the Necromancer.