I have a picky 5 year old and a 2 year old who is just entering the fussy phase. They will generally both eat the following as snacks:
Plain Greek yoghurt, or as a treat they like suckies yoghurt pouches - they are sweetened with fruit sugar but not too much and there are no preservatives etc
Home made sugar free banana or carrot muffins (you can DM me for recipe if you like!)
Hard boiled eggs (sometimes they won’t eat the yolk)
Banana oat pancakes (1 mashed banana, 2 eggs, 4 spoons of oats, mix up and cook little pancakes in butter or oil)
Nut butter or cream cheese sandwich
Plain rice cakes/oat cakes/crackers with hummus
Naked bars - these are very high in sugar so we don’t have them often, but they’re only made from nuts and dried fruits
Trail mix
Big chunk of peeled cucumber
Little cubes of cheese and cherry tomatoes
As much fruit as they can get their hands on!