op 10 one piece booster box TCG [OP-10] Royal Blood (Japanese) – Card Piece Includes a Variety of Powerful Characters ONE PIECE OP10 Booster Box

As you pointed out, the difference between Pokmon EX and Pokmon GX is that the former ones are always Basic whereas the latter ones are always the stage they are supposed to be [1] (except for Tag Team GX cards which are also always Basic)

Combos: Sliver Overlord + Amoeboid Changeling = Permanently steal any creature Sliver Overlord + Morophon, the Boundless + Mana Echoes = Play every sliver in the deck

And we haven't seen a copy up for sale since, until a recent eBay listing appeared, offering a PSA 8 graded version for some pocket change - if you have giant pockets that can hold $2,000,000 / 1,606,000 worth of change, that is

Condition: Brand NEW Brand:Pokemon Center Language:Japanese One 60-sheet deck (60 cards) * Due to the nature of the construction deck, there are multiple identical cards

English Cards Cards We Don't Buy And Trade Moderately played, Heavy played or damaged pokemon cards

You can only use this effect of "King's Sarcophagus" up to four times per turn