I read or re-read a manga, then i feel inspired enough to make a manga sig. I was gonna do a Akumetsu one, but its to sketchy art. As for other sigs, well anime is fucking insanely hard to find good renders for, or even good pictures to render(if your looking for non mainstream). I would try non-manga stuff, but.....the inspiration isn't rly there...
Only 3 things i would do.
1. Kung Fu movies
2. Heroes(tv show)
3. Me(yeah, once i get a haircut i'ma make one of myself.)