The Southwell chapter house green men are most familiar and well worth looking out for those at this weekend's FF. A favourite carved head (not a GM) is in Lincoln cathedral. It is a hominid-animal form that's is an absolute dead ringer for Goofy. Considering a nearby stall is for the parish of Norton D'Isney, ancestral home of Walt Disney I like to think of the dog as an animus who finally found a voice.
There also some interesting medieval pathologies (and older of course) depicted in Lincoln, toothache, migraine and so on plus unflattering characatures of the gaffer class.