The Shade Isle Campaign
After following a tunnel that twists and turns some 200 feet down into Thunder Table, one finds a huge cavern filled with natural columns and other beautiful geological formations, including quartz crystals studding the walls in many places. This cavern is inhabited by dozens of pechs, peaceful earth-sprites which do not attack intruders, but neither are they able to communicate with them. Neither spoken language nor gestures seem to help: the creatures simply answer all attempts to talk with dull stares, and they respond to hand-signals with imitation.
As near as the adventuring company was able to discern, the pechs didn’t have any possessions or signs of even rudimentary civilization, never mind treasure.