A while back, I put this spreadsheet together consisting of (definite and likely) sound origins from Heretic. A lot of these were dead ringers, some were taken from Kevin Schilder's remaining SFX notes for the game he sent to me, some are guesses, and others are sounds that perkristian found when he made a partial sfx pack that I haven't asked about yet. Regardless, 100+ sounds have been (at least partially) accounted for, and this could be a good foundation for a proper HQ SFX pack for Heretic.
I was going to make a video on this at some point, but lacked the motivation for the longest time. Ah well!
While I was writing this list, I put some of the sounds I've found together into perkristian's pack of his take on the Heretic sounds. I made a thread about that pack over here, and it accounts for over half of the sounds in Heretic. If you find any sounds I didn't account for either on the website I used to locate the sound effects, or any other site, let me know!