In Only One Collection, players are collecting cards hoping to have the most of each type, and the player on their right to have the second most! On their turn a player can either add a card from the deck to a set on the table or take a set. A player cannot add a duplicate number to a set. The game ends when a certain card is revealed in the deck. Then, the player who has the most cards of each number earns 1 point and then earns 1 point per card of those numbers held by the player on their right. The person with the most points wins.