a spec cards pokemon ace ACE SPEC card (TCG) Card Type / HP / Stage Pokemon ACE SPEC Cards Guide:

Adventure awaits as timelines collide in the Pokmon TCG:Scarlet & VioletParadox Riftexpansion

They sacrifice a lot of their own potential just to say, hey, remember this thing? even if it has nothing to do with the plot

Unmatched Nostalgia: A direct trip back in time, offering a chance to pull cards that define the franchise's history, reimagined with modern quality

For rebacked cards you can usually use the bend test (which will usually cause the two pieces to separate a bit near the crease)

It seems like many of the card treatments from the March of the Machine MTG set either didn't go down well, or were otherwise common enough that they became just as cheap, if not cheaper, than the regular cards