I get bored shooting paper so I have some favorite reactive targets on my home range. Wood - 2x4 and 2x6 chunks of lumber cut to 4 in. and 6 in. painted yellow. I'm a wood worker so I have used saw blades available, these are also painted yellow and hung by wire so they dance around when hit. Sometimes these come to rest so you have an edge shot (1/8 in.).
My all time favorite is ice. Freeze the water in various size round plastic tubs, pop them out of the container and refill. Sometimes it's a battle for space as these things multiply in the freezer. At the range set them up with the round end towards the shooter. They positively explode when hit, sending a shower of ice flakes in all directions. Biodegradable, no clean up.