Arrowhawk - no
Belker - no
Chuul - no
Digester - yes, once
Formian (Any) - Oddly enough yes. I resent them as failed attempts to replace the Modrons, but I've used LN/LG ones in Arcadia, and evil expanionist versions swarming across cubes in Acheron. They work -really- well in Acheron.
Grey Render - no
Grick - once
Howler - Pandemonium isn't Pandemonium without them *evil grin*
Krenshar - no
Kraken - no
Lillend - Yes, on the Infinite Staircase, in Ysgard, and as a PC (who sadly was sawed in half during a plot arc in Pandemonium...)
Phantom Fungus - No. Is there some kind of nostalgia these guys have for folks? Seriously, looking at their picture in the MM, they're the stupidest looking things on the face of the planet. I'd feel shame if I used one in a game. My players would mock me.
Purple Worm - no
Ravid - Yes, on the quasielemental plane of Ash, paraelemental magma, and the ash/fire border regions. They're great, but they need to be in their environment to really make sense. Their 2e writeup in the PSMC III was awesome.
Razor Boar - no
Shield Guardian - I've had some NPC spellcasters with them, or versions of them
Shocker Lizard - As an NPC spellcaster's familiar
Sphinx (any) - no
Yeth Hound - Yes, as servitors of a lich, of some Night Hags, and once as an experimental subject by some yugoloths
Xill - Yes, frequently in the deep ethereal, and occasionally in the border ethereal. Again, like the Ravid, the 3e version doesn't convey the best about them from 2e. The PSMC III once again had some incredibly disturbing stuff on them.
