im confused of what cards i can have and what i cant have please help
All unupgraded cards are allowed.
You must choose a main element for each deck. At least ~66% of the cards in your deck must be of the main element (see the table above for exact details), the rest may be of any element you like. Your mark may be of any element.
Each deck you play must follow these rules. You are allowed to use different decks and/or different main elements for each game.