Jetée, I've never seen garlic and onion jelly but I can imagine it tasting good with the right combination of ingredients....not sure about using it in peanut butter, that seems weird.
But there is another non-fruit combo in jelly that I do like, and even with peanut butter, and that's jalapeno jelly.
...it reminds me of hot combinations like Kung Pao chicken with hot chili peppers and peanuts.