Looking beyond thematic protection, we're a 5C deck so we have access to all the best options like Teferi's Protection, Heroic Intervention, the best countermagic like Swan Song, yadayada
Clockwork Avian looks less like an 'avian', and more like a monstrous pterosaur
If the product is opened heavily for the promos, complete opened supply sets may become harder to assemble
Youll run into: Tokens (usually standard size, but occasionally printed in other sizes depending on product) Emblems and checklist/helper cards (standard size) Oversized cards (promos, special products, Planechase planes, Archenemy schemes, Vanguard, and other delightful chaos)
It is also wise to have a price comparison app or reference handy, as prices can fluctuate dramatically between stores even within the same block
Chimecho (179/167) Mask of Change and Twilight Masquerade both contain some exceptionally interesting cards that feature underappreciated Pokemon