Among polyunsaturated fats, Omega-3 fatty acids help raise the level of HDL. Some fish (salmon, mackerel, lake trout, herring, halibut, albacore tuna, and sardines) are particularly high in omega-3, as are nuts like walnuts and almonds, sunflower seeds, and pumpkin seeds. (Make sure the nuts and seeds—excellent healthy snacks—are not sugar coated, processed with additional oils, or overly salted).
Olive, canola, safflower, peanut and corn oils are unsaturated and reduce LDL. An unsaturated butter substitute is better for cooking or as a topping than butter itself (since butter is mostly milk fat). With any fat or oil, however, purchase in small amounts, since fats become rancid relatively quickly, especially if stored at room temperature.