The Gruenaks were a race native to the world of Thra.
They're pale-green toad-like humanoids, around the size of Gelfling, but with greater strength. They possessed gnarled three-fingered claws.
The Gruenaks were a mechanically minded race that were nearly exterminated by the Skeksis during their campaign to conquer all of Thra.
- Dark Crystal: The Age of Resistance: What Was Sundered and Undone (2019)