Noticed that you really like pineapple. Not one of my favs.There are quite a few fruit combos I like. Don't think I can pick favorites, too hard.
Apple/pear, orange/grapefruit, apricot/apple, pineapple/mango, kiwi/passionfruit, orange/pineapple, starfruit/grapefruit, strawberry/grapefruit, pineapple/strawberry.
There are more...
I've used the above combos with different bases of mine. Usually 10mls of a base and then add a fruit combo.