https://subeta.net/subetapedia/pet_combos.php?act=search&color=0&species=76

The Common Aeanoid is listed twice on its species page. Once at the beginning, like all the common pets, and once between Chibi and Cream, where Common goes alphabetically.

It's the only one I've seen so far which does this, all the others have Common up front and nothing between Chibi and Cream.