The 4 variations of Omaha Poker are:
1. Pot Limit Omaha High, also known as PLO, where the highest hand wins and there is pot-betting limit.
2. Pot Limit Omaha High-Lo, which is known as PLO8, where the pot is split between the highest hand of poker and the lowest hand that contains 5 cards of 8 or lower.
3. Fixed Limit Omaha High, where the highest hand wins the showdown or fixed bet amounts.
4. Fixed Omaha Hi-Lo, where the pot is split at showdown or at the fixed bet amount.