KOFFE is a 2D fighting game engine compatible with KOF'91. Written in Object Pascal, it's very configurable: it's possible to change all character definitions, backgrounds, sounds and graphics.
VoxRend is an OpenSource voxel graphic engine. It can be used to create games or simulations, but you can use it to get other graphic representations. Uses tile-maps and can load and render Ken's VOX files. Today it's inactive but I have plans for the