I actually haven’t, which is surprising because you’d think they’d fit right in with the grotesques that were so popular in manuscripts. Humanoids and beasts don’t really show up in the same places, though, so I might have just missed them. I’ll keep an eye open in the future.
they’re also called monopods or sciapods and there are plenty of examples on wikimedia so i pulled some up for ya
from the nuremberg chronicle, 1493:
from the heures à l'usage des antonins, 15th century:
from sebastien munster’s cosmographia, 1544 (with bonus cyclops, conjoined twins, blemmye & furry)
and another one with a blemmye, from the livre des merveilles of ca 1410:
awesome, thank you! I knew there were some out there.