Humans:
[url=http://www.zerochan.net/1244798]A villain who's so bad yet so destructive OR has super speed and invisibility[/url]
[url=http://www.zerochan.net/830249]Spoiled rich crazy girl and her genius, murderous butler[/url]
[url=http://www.zerochan.net/1498601]Invisibility and super speed? Or maybe shadow manipulation[/url]
[url=http://www.zerochan.net/223199]Evil twins. Maybe they can be the masters of disguise? Or they could have some weird psychic twin link shit[/url]
[url=http://www.zerochan.net/1268905]Person who's art turns into monsters and weapons and stuff[/url]
[url=http://www.zerochan.net/1315436]Somewhat androgynous master of disguise[/url]
[url=http://www.zerochan.net/432857]PUPPET MASTER GIRL WHO HAS MAGIC STRINGS WHICH CONTROL PEOPLE[/url]

Monster-ish:
[url=http://www.zerochan.net/234816]Girl and her evil cursed protector that is actually just a suit of armor[/url]
[url=http://www.zerochan.net/720977]Big cyborg guy with human brain but robot body[/url]
[url=http://www.zerochan.net/84687]Girl with legit monster hair[/url]
[url=http://www.zerochan.net/1688185]alien[/url]
[url=http://www.zerochan.net/552789]alien[/url]
[url=http://www.zerochan.net/789813]misunderstood alien and his little human pet[/url]

I can find more if needed but those are just ideas