Software I have made. It is mainly for my own use, so don’t expect anything actually useful.
Change the pitch of a WAV file. No resampling, no loss of information. How? Simply changing the samplerate. I use this mainly for romhacking, which requires samples to be pitched to middle C.
Calculate approximations of ADSR envelope values to and from the GBA Sappy engine and the NDS Nitro engine. For romhacking purposes. It is buggy, unoptimized, ugly, and imperfect. This was my first application for anything ever.