WOTC-20 is a historic fan-created format that includes all of the sets produced by Wizards of the Coast, from Base through Skyridge. Given access to such a broad and powerful set of synergistic trainer cards, decks are restricted to 20 trainers in order to facilitate interesting choices and diverse gamplay.
For more information about the rules, ban list, and erratas for the format as well as information on where to find games: https://gamesirl.com/wotc20
The card pool defines which cards are legal in this format. It starts with a search query against all cards in the game, then optional include/ban lists refine the result.
set:base-set, OR set:fossil, OR set:jungle, OR set:base-set-2, OR set:team-rocket, OR set:gym-heroes, OR set:gym-challenge, OR set:southern-islands, OR set:neo-genesis, OR set:neo-discovery, OR set:neo-revelation, OR set:neo-destiny, OR set:wizards-black-star-promos, OR set:aquapolis, OR set:skyridge, OR set:expedition, OR set:vending-machineValidation filters are extra deck-building rules beyond the card pool. They restrict which decks are legal — for example, limiting the number of cards of a certain type, enforcing a star budget, or requiring a specific theme deck.
Cards matching: type:trainer
Allowed in deck: at most 20