We've been enjoying frozen bananas as summer snacks. I freeze them peeled in a baggie (they need to be ripe, but not overly ripe as they get brown and slimy...) She enjoys letting them thaw a little and then using one of her Ikea knives to cut them into pieces. You could mash them for kids new to finger foods. they gat a creamy consistency like ice-cream almost. We continue to enjoy frozen blueberries and are looking forward to trying frozen grapes. (Remember that nuts and grapes and blueberries are not appropriate for very small children unless prepared properly for their skill level-ie grapes quartered...)
M hasn't taken to nuts very quickly which is sad as they are such a wholesome treat to add to snacks with protein and good fats. (Remember every snack and meal should offer fat, protein and carb.) We bought a massive bag of pistachios from Sams Club and have offered them over several days. Today she rejoiced that she could crack them open and ate several without comment. Pistachios are a great nut for "picky" kids. The act of opening them makes them "fun," and for kids who like saltier things, its a great intro to nuts.