There's a tonne of these.. Most samplers can do it, in my Maschine I can flip a switch and it'll play any sample in reverse. There's also a whole lot of buffer and stutter effects on the market, they take incoming audio, chop it and, among other things, reverse it on the go. It's a pretty nifty effect, but also one that wears out it's welcome quickly and doesn't take a whole lot of skill or originality to pull off. Used sparingly it's pretty effective though.