There are Exactly 52 poker hands. Here is a list of all 52 hands, with their rankings and descriptions:
Aces High: Highest ranking card. Can be used to make any bet.
Aces Low: Lowest ranking card.
Two Pair: Two cards of the same rank.
Three of a Kind: Three cards of the same rank.
Straight: A single card, usually a 10 or a Jack, ranked as either high or low.
Flush: Five cards of the same suit, including the Ace.
Full House: Three cards of the same rank and two cards of the same suit.
Four of a Kind: Four cards of the same rank.
Straight Flush: Five consecutive cards of the same suit, starting with the Ace.
