This can be clues and treasure tokens, the lesser ground based 1/1 servo tokens that crop up, Talisman and Signets past their best, a Mox (ideally an unimprinted one!) and so forth
But XY is past, and in this go-around, we have zero capital letters in the "ex", so, do we have to explain the meaning to all, and find it too complex to understand in the eyes of some who weren't here when XY was, or can we interpret this go-around as a different way to Mega evolve, TCG-style, and remake mega turbo under a different name, and leave the past alone as "different", just like NVI's Eelektrik compared to BLK's Eelektrik
The big downside to Palafin Ex, though, is it can only be evolved using Palafin's Zero to Hero ability, which makes it a little cumbersome to use
Common Pokmon cards are definitely worth collecting, especially if you enjoy completing sets, building playable decks, or collecting cards based on specific Pokmon