What, no Tome of Horrors? Some of the best and oldest creatures are in there. =o)
Apparition (1e FF)
Barrow Wight (new)
Bhute (new)
Bloody Bones (new)
Bog Mummy (2e RtWPM)
Coffer Corpse (1e FF)
Crypt Thing (1e FF)
Crypt Guardian (1e FF)
Darnoc (new)
Demiurge (new)
Demon, Orcus (p1e EW and 1eMM) I know not undead but if you are talking about undead how can you not give Orcus an honorable mention? =op
Draug (new)
Ghoul Stirge (new)
Groaning Spirit (1e MM)
Haunt (1e SotSS)
Huecuva (1e FF)
Mummy of the Deep (new)
Phantom (1e SotSS)
Poltergeist (1e FF)
Shadow Rats (new)
Shadow, Lesser (new)
Skulleton (new)
Ghoul Wolf (new)
Shadow Wolf (new)
Zombie, Brine (new)
Zombie, Juju (1e MMII)
Template, Skeleton Warrior (1e FF)
Template, Slime Zombie (1e LCoT)
Template, Spectral Troll (1e MM)
Only reason I mentioned these and not other S&S undead creatures from CC and CCII are because most of these are converted original D&D undead that we are all fond of and use to from 1e. =o)