SFZ

An SFZ file is ordinary text with headers such as <region> and <group> followed by opcodes, for example sample=piano_c4.wav lokey=58 hikey=62 lovel=0 hivel=64. The samples themselves stay alongside as separate WAV or FLAC files. The format was developed by rgc:audio in the mid-2000s and came along when Cakewalk bought the company — an open counterpart to SoundFont and its binary bundles.

The upside is that an instrument can be written, version-controlled and grepped with a text editor. The downside is that every player implements its own subset of opcodes. Free players such as sfizz and Plogue's Sforzando have made it the de facto format for free sampled-instrument libraries.