Legos are always great. Art supplies, or art that doesn't require supplies, like etch a sketch, or a tablet that you can draw on again and again, or reversible pin games. Science kits are a favorite. In summer, you can never have enough pool stuff, goggles, cool towels, carry bags. Also, garden sets with kid size gloves, kneeling pads, some small plants and pot to start a pizza garden (basil, pepper, cherry tomatoes). Get them a fanny pack in a cool color loaded with sun screen, bug lotion, and funky hiking hat. Bug Catchers, magnifying glasses and magnets. Books like Captain Underpants or How to train your dragon, anything Roald Dahl, Wrinkle in Time, Harry Potter Series.