Pokemon TCG

For anyone not in the know, the life count for magic is 20 whilst the other games are in the thousands.

This is a vintage monster that had two halves and costs 15 swamps to play.
(A swamp is one of 5 land types you could play to pay for units, and only one could go on your field per turn under normal circumstances).

It is the highest damage non joke card I can think of. Not many modern era cards go over 10 attack, usually it's more optimal to get a higher on one unit via effect stacking or multiplication.

One way I've seen people deal broken amounts of legal damage in MTG is by token spawn spam, where sometimes you can just spawn any ammount of tokens so long as it's a real number.