What is Gym Leader Challenge?
Gym Leader Challenge (“GLC” for short) is a fun, challenging, and diverse format that lets you use a much larger pool of cards than the typical Standard format we use in tournaments! In Gym Leader Challenge, players specialize in a single type of Pokémon and build their deck only using that type of Pokémon, like a Gym Leader would!
The Rules
Your 60-card deck can only contain one type (or color) of Pokémon.

Only one of each card with the same name is allowed in a deck, except for Basic Energy.
Cards with a Rule Box are not allowed (EX, GX, ex, V, Radiant, Prism Star, ACE SPEC, etc.)
It uses the Expanded format, which is Black & White base set onwards.
Clarification and Restrictions
You can have multiple types of Basic Energy cards in the deck (good news for Dragon types!)
Dual-type Pokémon are allowed, as long as one of the types matches the theme of the deck.
Pokémon with Ancient Traits are allowed.

You can have Boss’s Orders or Lysandre in your deck – not both.

You cannot have Professor’s Research, Professor Sycamore, and Professor Juniper in your deck – you must choose one or the other.

Cards from World Championship decks, which are normally not tournament legal, CAN be used in GLC!
Certain cards are banned from play in GLC. Even though GLC uses the Expanded format, it has its own ban list that does not include most of the cards banned in the official Expanded format. See below for cards not allowed. Click here for the official list and reasonings for their removal from the format.