Farmers markets very occasionally will have interesting fruit, often I suspect as a side project for the farmer, sitting at the back of their stall for a couple of weeks only.
In Californian farmers markets and fruit stalls I've been able to get some relatively uncommon fruit with unique flavours: feijoa, persimmon, passionfruit, pomegranate.
Travel is another way to be exposed to new fruit via alternate supply chains. Most Americans have never heard of feijoa but New Zealand in autumn is awash with them! You don't even need to buy them cause everyone has a friend, relative or neighbour with a tree trying to git rid of theirs before they go off!
https://thespinoff.co.nz/society/04-04-2017/in-praise-of-the...