The best fruit to grow is the fruit you like to eat.
And then it's good to grow a variety that you like that you can't buy easily in the shops, or that is expensive in the shops.
I want to grow an apricot tree because the taste of fresh apricots is so much better than the taste of apricots bought in supermarkets and shops.
Some varieties of fruit tree need to be near to others (of specific types) so that they can be successfully pollinated by insects visiting both trees in succession, passing the pollen from one tree to another, so it can be quite complicated deciding what variety of tree to plant.
But if, for example, you like pears, and the garden next door has a pear tree growing in it, you could find out which type of pear it is and choose one of the other pear trees that can be fertilised by your neighbour's tree, so you don't necessarily have to grow two trees yourself. Some varieties of tree are described as self-fertile, but they will always give a bigger crop if they have a suitable pollinating partner nearby.
But your first decision must be what sort of fruit do you like to eat?