I've been impressed with my set of bamboo blend underwear from Boody, specifically the underpants. I bought like 8 pairs over a decade ago, and when I bought another set a few years ago and mixed them into the old pairs it was hard to tell the difference. I machine wash them and air dry them and they've held up extremely well. They're so soft and comfortable I can't really feel them when they're on, which is remarkable because I have trouble filtering sensory things.
They've held up so well after hundreds of wears I feel good recommending them to others. They ARE very simple, but they come in a variety of fits and colors.