We don't know a whole lot about heraldry as of yet, here's some heraldry examples that were given to us a couple years ago when SbS had a jousting demo at PAX W.
As someone who does custom CoA - I think a lot of people get them made to show something off in their other media (forum posts, discord, personal websites) and keep is simpler & CoE oriented (ie. I see more realistic animals, medieval theme, than anything high fantasy)