A Combo Priest is a deck that largely sticks to its game plan and only disrupts the opponent when necessary. You’re not looking to trade resources unless you absolutely need to, and every card in the deck will either enable the combo or prevent the opponent from killing you before you can do so. Combo Priest decks have come and gone as new cards got introduced, but always relied on the base cards that pump a minion to obscene stats. You can tinker with other minions and cards to get more value and adjust to the metagame, but you usually won’t be able to go without the core package.