So I complied a list of all the monsters I might need and then ran it against my
painted miniature collection, and this is what I've got:
Bear -- 02878: Dire Bear
Boar -- 02527: Dire Boar
Construct, Large -- 02751: Stone Golem
Construct, Medium -- 02596: Schindal, Clay Golem
Construct, Small -- 02865: Flesh Golem
Demon, Minor -- 02712: Eyebeast
Demon, Major -- 02684: Frog Demon
Frost Giant -- 65111: Frost Giant Warrior (out of print). The only one I already have photographed:

Ghoul -- 2 ghouls from 02941: Ghouls and Ghast
Giant Rat -- 02889: Dire Rats
Imp -- Imp from 02756: Familiar Pack IV
Skeleton -- GW Vampire Counts Skeletons (4)
Vampire -- Vampiress from 02990: Crypt of the Vampiress
Werewolf -- 02872: Male Werewolf
White Gorilla -- 03088: Bagheera, Demonic Ape -- and when I painted this guy up years ago, I greenstuffed over the wing sockets because I needed a carnivorous ape, not a winged ape. So he's perfect! He's even light grey!
Wolf -- 1 wolf from 02415: Dire Wolves
Worm -- 03009: Purple Worm
Wraith -- 02103: Murkillor The Wraith
Zombie -- GW Vampire Counts Zombies
All part numbers are Reaper product codes.
I am really happy that I finally have a use for a lot of these RPG monsters I bought for one game that never see use. Like the Dire Boar? Bought that for a Pathfinder adventure, haven't used it for anything since. Same with the bear. Some of these I've never had a chance to use, like the Frost Giant, Purple Worm and Golems.