I have an Incase metalic case on my Airpods Pro. I like having the case on them, mostly cause I managed to drop them like 3 times in the first week of owning them (including once where they slid out of my pocket when laying on the couch) plus they manage to pick up a lot lint in my pocket without it. I can't necessarily recommend that particular case though - it's annoying to remove (I made a bit of a noticeable scratch trying once - best way I found involved using a lightning cable plugged in, which I don't love), it stopped them from working with my (admittedly cheap) Qi charger, and I kinda wish the texture was a little more grippy.