The real questions are whether you can actually sell anything or whether it's for own use..'cso there's only so much you can eat and folk generally don't want to buy low quality fruit..so commercial growing is a serious business.
Knock yourself out with this link.. an amazing selection might well grow in S Wales
https://www.agroforestry.co.uk/product-category/plants/I do move my citrus into winter quarters..and yes they get heavier every year.
Apart from the usual apples, pears, plums (several varieties) cherries, gages, medlars I;ve got here I've also got an apricot, peach (neither has borne yet) hazel, walnut, sweet chestnut, almond, monkey puzzle (yes they have edible seeds too), pecans, hickory nuts... but those nut trees will probably not bear in my lifetime. There;s soft fruit bushes of course.. everyhting from blueberries through honey berries to jostaberries and currants... but with all that sort of stuff it's a question of whether you can protect it from the birdies..much as the cherries and the wasps on the plums and damsons.
In the west country they are successfully growing tea, you could also consider grapes, kiwi, passion fruit and everything I've forgotten - blackthorn for the sloes (but I rip them up after all the punctures), elderberry, rosehips, blackberries.... it's endless.. Oh, how about a strawberry tree they grow in west Ireland? And never forget the figs!- the sexiest fruit you can grow.
As for your disdain of apples.. well go look at some of the varieties available that you can't easily buy - heritage russets, juicing apples...it all depends on your market and micro climate.. theres even folk trying to grow their own dates.
In my madder past I've grown bananas, figs, grapes and pineapple. I've tried unsuccessfuly with the bread fruit, avocado and sapodilla and lychee (yes in greenhouses although the banana spent the winter in the dining room|)