Driving myself crazy that I cannot source these
these last few midis, taken Doom 2 Xtreme and its sequel, Doom 2 Xtreme Gold. I've been able to gradually identify all the midis used across both wads, but these last few just seem hopeless thus far. A few of them have a sense of familiarity, but nothing is ringing a bell otherwise. They had to have come from games/movies/midi pages/etc. dated no later than 1997, but where to even begin looking is trying my patience.
Another midi I thought I might have identified but am not confident about is
this one, often circulated as "alien.mid" and claiming to be the theme from Alien, though it is clearly not. I found the midi also named "dkc3undr.mid", implying a Donkey Kong Country 3 source, but it doesn't match any song from the game. It was once listed on VGmusic.com for that game as "Underground", but there is no level with that title, and has since been removed from the website, so something seems fishy with this one. I've also heard it claimed that the midi is from Dawn of the Dead (1978), but again, it does not match any song from that film.
ADDENDUM: "alien.mid" was also featured in Doom 2 Xtreme, which was apparently released in August of 1996, going by its DeHackEd file. DKC3 came out in fall of 1996, meaning it couldn't possibly be a midi of anything from that game. Hmm.