I have always preferred grass for most of my plyo work, especially when it comes to the bigger jumps, like skips for distance.
I’ve also had good experiences at the gym doing plyos in the aerobics/group exercise room (when no one else is in it). The wood-over-rubber floor always felt extra bouncy to me and didn’t feel like I was destroying my joints and shins.
It is even more fun doing them in the aerobics room when people ARE in it 🙂 You get some strange looks when you begin stacking aerobic steps against the wall to do box jumps!