Boiled eggs
Egg bites (like mini baked omelette done in muffin tins)
Cheese
Make some cheese crackers
Make small cakes/biscuits/flapjacks wtc
Plain yoghurt and berries
Cold meats, left over roast chicken etc.
Try different veggies, like sugar snap peas, mini corn on the cob, pickled veggies.
Nuts.
Peanut butter and celery.
Cheese melts (literally grate some cheese, out in a small pile on baking tray and grill it toll crispy)
Make some pastry and make tarts, sweet or savoury.
Make baba ganoush/hummus/tzatziki or similar and have with flat breads (tortilla are easy and yoghurt flatbread)
Make your own nachos, with aforementioned tortilla, grilled up with cheese and chopped tomatoes etc.