can you buy pokemon cards on amazon 50+ Official Collection with 5 Foils in Any Combination and at Least 1 Rarity, GX, EX, FA, Tag Team, Or Secret Rare : Toys & Games Pokémon TCG: Mega Evolution—Pitch Black

Yes, these cards are legal in any format where the original printing of the card is allowed, such as Commander, Legacy, or Modern.

In the cat deck, Plains are what you want anyways

You can build decks with the aim of attacking mana bases and do so with bounce fairly well and Into the Roil has no place in such decks

but also the fantasy of a large winged lizard that's just a wild animal

Shorikai has an incredibly high power ceiling, being able to go infinite with Intruder Alarm and doing evil things with Unwinding Clock and Skullclamp which are outside the budget range of this deck, but they are available if you want to upgrade