Hey, they're not unreasonable. I mean, no one's gonna eat your eyes.
I've got a few slightly altered takes on critters I've used in my games, two of which really stand out:
The Hobgoblin Khans - These make an appearance in all my campaign worlds. Rather than clumping up in fortresses and marching out Uruk-hai-like to smash handy settlements, they are masters of mounted combat and spend most of their lives on horseback. They dominate the high steppes under a loose knit federation of nomadic tribes constantly vying for dominance (through direct conflict, but also through displays of captured wealth). Only the greatest warriors can hope to claw their way to the title of Great Khan, and when one arises the neighboring lands tremble in fear at the prospect of a thundering orange-skinned horde descending upon them.
The Goblin Keldas - This idea came about out of my desire to throw whole tribes worth of evil humanoids at my players without winding up with a Garriot-esque moral dilema when the players fought through all the baddies only to find the nursery. Goblins in this world are like a mix of rats and hive insects: breeding females are vanishingly rare, but make up for it by staying almost continuously pregnant during the fertile portion of their life and by giving birth to huge litters. Their spawn reach maturity shockingly fast, which leads to massive population pressure. The Keldas, those few females who survive their breeding years to become leaders of the tribe, release this pressure by periodically sending out 'raiding parties' and 'warbands' from their homes deep in the underdark, ranging from a few dozen to a few hundred goblins. Most never return, which suits the Keldas just fine. When the time comes for a Kelda to step down from the council, usually due to infirmity, senility or madness, she is put in charge of one of these grand expeditions. The male goblins, clever as they may be, have a blind spot when it comes to their females, and will follow even the most moon-addled old hag without question. Because of all this, most bands that adventurers will meet are composed entirely of combatant males, rarely accompanied by a wrinkled and possibly quite mad witch doctor. They also tend to be composed of the young, the dangerously psychotic (even compared to normal goblins) or those getting on in years. Deep delvers will find that they get significantly nastier (and higher in challenge rating) the closer one gets to the goblin homelands, with the lairs themselves guarded by a fanatical elite.
