Tilificator is a sprite conversion tool I wrote to try to solve an annoying problem I’ve always had with sprite graphics for the NES: How to create CHR and sprite data that re-uses CHR patterns and tries to minimize the sprites per scanline, without lots of repetitive effort.
To do this for you, it uses some clever heuristics, and a lot of brute-force, trading artist time for computer time. It’s a work in progress, and will still produce bad results for some seemingly obvious cases. But it’ll probably do the job better for big amounts of sprite data unless you’re dedicated to hand-optimizing your sprites. :)
SourceForge.net: Tilificator – Project Web Hosting – Open Source Software.