How about Common Rose, Common Jay, Common Bluebottle, Common Grass Yellow, Common Tiger, Common Tree Nymph, Common Faun, Common Sailor, Common Hedge Blue, Common Caerulean, Common Line Blue, Common Imperial, Common Posy, Common Tit, Common Red Flash, Common Awl, Common Snow Flat, Common Dartlet, ... ... ... ...
The truth is, some of these 'common' butts are actually very rare.