Some very good mods, in no particular order:
mod.abiturientti (from Closer/Carillon Cyberiad demo, tp95 winner, not everyone likes this one by Groo, but imo it rocks)
mod.desert dream-titel (== mod.checknobankh) (from Desert Dream / Kefrens demo, tg93 winner, laxity classic)
mod.desert dream-end (from Desert Dream / Kefrens demo, tg93 winner, laxity classic)
mod.cream of the earth (Cebit Demo 90 / TCC Design,Red Sector Inc, Romeo Knight rocks)
mod.livin' insanity (from ARTE / Sanity demo, tp93 3rd, moby rules)
mod.knullakuk (from Substance / Quartex & Alliance design demo, moby rules even more!)
mod.trip to mars (from Diznee Land #2/ Abyss, chip goodness by Meo)
mod.sleeping waste (from some pc demo, some serious chip goodness, again by Meo)
mod.gatecrashing-4 (from Comadose / Passion, more chip goodness, this one from Subject)
mod.we're the devils (used in various demos. Very nice one from Walkman)
mod.switchback [main] (from Switchback / Rebels demo, Doom's Day Party 1994 winner)
Okay that's 11, sorry about that. I could list dozens more, easily... :-)
Bonus tracks, non-ProTracker ones:
sid1.beat to the pulp (from The Real Dinkelator Doppelbock / Tristar & Red Sector Inc, Romeo Knight ownage)
aon.shadow zone (by DSN)
hip.prehistoric tale [title] (by Jochen Hippel, later covers by Jogeir Liljedahl suck)
hip.gates of jambala [intro] (from Blah Blah I/Sanity musicdisk, true classic by Mad Max)
fp.imploder [main] (from Turbo Imploder 3.0 packer program, by Paul Van Der Valk)
mods.lha - the abovementioned modules
I'm using
UADE to play mods these days (on Pegasos II).