Plenty of free trackers out there which can produce .xm & .it output compatible with Blitz3D.
If you don't mind slightly larger files (.wav -> .ogg) I would recommend using Buzz www.buzzmachines.com which has supplied many years of fun for me.
If you don't mind slightly larger files (.wav -> .ogg) I would recommend using Buzz www.buzzmachines.com which has supplied many years of fun for me.