According to CGC, the last one, which is printed on a plain backing and not the usual MTG or Pokmon designs, was actually a press asset used to show off the card game for a now-lost interview
Some base cards have kind of a glossy back instead of the normal printing
Cranial Plating was the replacement for Skullclamp in Affinity, and the deck may have gotten worse but it wasn't that big a blow
Weird Angel Flame, for example, grants a heroic ability, but it can also grant protection from (checks notes) even mana values
Familiarise yourself with the feel, weight, and print style of real cards
It mainly appears on black and red creatures, but every color has access to cards with menace