ROM and Emulation can hold a lot of contribution. Here is a list of examples of contributions that could be made.

Clean ROM sharing. (Self ripped or shared from DL/ROM sites)
AP Pre-Patched ROM sharing. (Again, self ripped or shared)
AP Patchers for a certain ROM, or one for most/general ROMs
Flash Cart compatibility rates. It's important for a flash cart user to know if the ROM will be compatible with their flash cart or not.