No worries about growing zone, weather, space requirements just your dream garden.
I would love to be able to grow vanilla, they look really cool the flowers smell amazing and having a source of fresh vanilla beans would probably unlock some next level cooking. An olive tree would be cool too, I can eat unlimited olives and making my own oil would be awesome.
A cherimoya tree.
They are the best fruit, hands down. Verified by Mark Twain who called it "the most delicious fruit known to man".
However, the trees grow like twelve fucking metres tall, and they absolutely cannot tolerate frost, so it's kind of a non-starter where I live