We used the neco wafers, asprin tablets (600n targets to a bottle), eggs, ice cubes. pasta shells noodles. A light ping pong ball with an air rifle might be fun for a game we used to play with 22s and golf balls. Every one puts their initals on a ball and pace it at the starting distance. Everyone gets 10 pellets to se how far they can drive their ball the farthest.
Reactive targets are good if you can find some electrical box knock out slugs they make good small gongs for air rifles.