Omaha Hi-Lo with 5 hole cards.
With more hole cards, everyone tends to hold a low, so only the nut low wins. Example: when the low cards on the board are 3-5-8, A-2 makes 8-5-3-2-A, the best low. A-4 makes 8-5-4-3-A and loses to A-2. You make your high and low from exactly 2 of your 5 hole cards and 3 from the board, and it is usually pot-limit.