What are some examples of such loop settings and how would you store them in the .wav files? (I’m curious if there’s any standard labels/names for loop markers that I’m not aware of.)
I hope I’m understanding your question well enough.
The WAV format already supports loops. If you save a sample with a loop in it, the loop will be understood by other samplers, or any software that supports loops. If you load a sample with a loop in it, the loop will appear in Renoise (this behaviour can be changed - in Preferences I think - but it is on by default).