You're probably noticing a certain green theme of taking any given number and multiplying it by two
All sorts of things can ruin cards: Sweat, oil from hair and bathroom products, food crumbs, fingernails, spilled drinks you name it
You can choose from many Pokmon TCG sets on the sets page, including modern favourites and older expansions where they are available in the simulator
What's more, Hasbro is working on a Magic: The Gathering film and TV series too.
Love this cycle loads since you don't know what folks are bringing to your metagame, so these are very flexible for board state and removal
Credit: Wizards of the Coast Furnace Hellkite FromTheShire: I don't know that this slots in anywhere right away, but it's a lot of stats for potentially 2 mana