DS does NOT eat plain, unadulterated fruit (I still offer it every day) and I don't buy processed foods, so I hear you. I'm always on the lookout for easy healthy (preferably fruit-based) snacks.

These are our go-to snacks:
Corn cakes, puffed rice, puffed corn (both from the health section - taste like cardboard, but DS eats them, so that's all that matters!), banana chips (found one brand in the fruit shop that's 96% banana and no flavourings), grated cheese. Plus, we always have a freezer full of stuff like 'everyday icecream' (fruit and egg whites), homemade ice blocks (fruit and yoghurt), homemade muffins (w meal flour, no white sugar, puréed fruit), banana pike lets, bikkies, slices etc that DS can eat (he prefers them frozen!).

Sometimes he'll have bran 'worms', oat clusters or just plain dry oats. Occasionally he'll want frozen peach ice cubes or frozen berries, which makes this mummy do handstands, as its pure fruit! Or maybe raw carrot or a whole flat mushroom (a fave when we go shopping - i have to go back, pay for one mushroom, then cop looks from people who think we haven't paid for it). Ok, so DS is a weirdo!

Currently looking into homemade oat clusters, so the oat/ banana things might work for that. And, homemade muesli bars that I can keep in the freezer.

We also went through a chocolate ball stage - blended up nuts, dried fruit and rolled in coconut, but these are out of favour at the moment.