This is the official site of the FlatRedBall engine, used as the basis of the Kokusai Fighting Engine. This is a wonderful engine written in C# and XNA dedicated to simplifying game development. Very well documented, frequently updated and with an active community.
There are a lot of websites dedicated to MUGEN, but this is one of the best. There is a lot of free downloadable resources like characters, stages, tools, everything you need to work with the MUGEN engine.
ShugenDo is a 2D fighting engine based on the MUGEN fighting engine from Elecbyte. Compatible with the MUGEN char format, it improves this engine with more features like dynamic stages, hardware accelerated rendering and network play.
GIMP is a free software, raster graphics editor used to process digital graphics and photographs. It is often used as a replacement for Adobe Photoshop, the most widely used bitmap editor in the printing and graphics industries; however, it is not designed to be a Photoshop clone.