I suggest looking into the Square Circle illusion. As long as it's made well, you can do it with cardboard and construction paper. With it, you can conjure anything from live rabbits to filled goldfish bowls.
I'd also recommend the oil painting illusion, which was featured in the movie The Illusionist. I found the instructions to this illusion in an old book, I have no idea where to find it these days. The name should give you a hint, though. There's also the Arabian Tent illusion, which can be made out of wood, or it's cardboard counterpart, Victory Cartons, and another one, my book calls it the mummy's casket, but it's basically a telephone booth sized box with a door at either end, and you conjure your assistant from it after showing it empty. You could also try the Chinese Snow illusion. I myself use a variant; I found a card trick finale where the deck is covered with a hankie, thrown into the air, and bursts into a cloud of paper bits. I combined this with the "butterflies" variant of the chinese snow illusion. The deck is thrown into the air, turns into paper butterflies. I pick up a couple of them, use a fan to make them dance, slap them, and clouds of butterflies fly up.
For kids, I suggest the PBJ illusion, which is easily homemade.
For smaller illusions, I suggest the Vase of Allah, Utility Cone/double walled bag/change bag, magic coloring book, wine glass production,