If you like characters mostly accurate to the source then the following might interest you:

- Kamekaze/REDHOT's MvC2 conversions
- warusaki3's JoJo & CvS2 conversions
- GM's SF3 conversions
- muteki's Guilty Gear conversions

For good custom stuff, Team Z2 makes great Dragon Ball characters. Lastly, P.o.t.S' characters are also popular, and for good reason.