everything high in unsaturated fats (nuts, oils, fish etc)
I'd go with peanuts, or any nuts really. Extra light tasting olive oil is great too. 1/4 cup will add a bunch of calories to a protein shake and you won't notice the taste difference.
Only animal products should contain cholesterol.
So, eat non-animal products...
Dietary cholesterol doesn't have much to do with increasing or decreasing cholesterol in your blood. It does tend to come along in the same foods as saturated fats, though, which led to our thinking that it was a big factor for a while there in the '80s or so.
Avoid saturated fats. Another vote for olive oil and nuts, and I'd add lean meats, particularly fish.