from MM:
hydra. choker. beholder and variants. undead things with energy/stat drain.
from Fiend Folio:
cuprilach: full attack as standard action.
sarkrith thane: extra standard action/round, 9/day
sunwyrm: 8x normal sight.
skulk: run while hiding with no penalties
sea drake: all damage are nonlethal so long as it's in water
rukanyr: sundering roar: 12d6 damage against single creature within 60 feet, or you can use it to sunder with almost guaranteed success.
from MMIII:
arrow demon: you won't find a better archer anywhere.