I just looked in the Fiend Folio. No shocker lizards, just shockers and volts.
And I have used grey renders, to great effect, twice. One was the henchman of an evil fighter it had "bonded" with, and the other was an experimental test animal owned by a necromancer. The party's necromancer animated it once it was slain and rode around in its ribcage.
And I will agree that beholders have waned in use since 2e. In 3.0, they had bad armor class and few hit points. 3.5 have done something to correct this, fortunately.
I'll agree that chokers and chuuls are underappreciated, but I'd like to add another aberration to the pile- the athach. I have never even heard of these non-giants getting played.
Demiurge out.