|No, not that one.|
True, they are more commonly seen as a player race, but even then they’re hardly ever seen, largely due to the broken nature of Psionics. However, my favourite aberration has to be the Elan, a mysterious race of near-immortal humanoids, not born but made in secret ceremonies known to none. They are humans which have been imbued with psionic energy which means that their bodies are largely sustained by the power of their minds, which means they can live almost indefinitely, can sustain themselves on psionic energy, and can fortify their bodies in the same way. This race from the Expanded Psionics Handbook is great to play, as they have all the appearances of being human, but can have hundreds of years of experience to draw upon.
I have never seen them used as a monster, but I really think they should be. They are almost indistinguishable from humans, as that’s what they were once, but an Elan that looks 21 can really be over 400, and this creates great potential for intrigue. On top of all of this, Elans are abberations. This means that Charm/Dominate Person, Hold Person, etc. will not work on them, which could be a great surprise for the party if you happen to have an enchanter around.