Most seafood. Shellfish specifically, but anything fishy smelling / tasting will do it.
When I was 10ish, my parents threw a small party, and people were eating shrimp with cocktail sauce. I decided to "act like the adults" and try one... except, no one told me you were supposed to peel it first. Crunch crunch crunch, *hurl*. I still enjoy canned tuna if mixed a very specific way, I've eaten breaded crab cakes that I enjoyed, I've had really good smoked salmon, but lobster, shrimp, or any sort of fish by itself makes me sick just from the smell, let alone the taste.
On my brother's 12th (?) birthday (Dec 23rd), he had some cheap yellow cake with nasty vanilla frosting, nasty vanilla ice cream, and egg nog. The combo of all three together was just way too much, and I got sick. To this day, I can't drink egg nog, and some dairy products still turn my stomach. I can only drink milk if it's ice cold, or with certain things like chocolate or peanut butter. I do enjoy yogurt and certain cheeses, though.