I've been playing around with property-based testing in Racket this past week. I started by forking the existing quickcheck library to try and add support for shrinking, but I quickly realized that I'd have to make a number of breaking changes to get it to work the way I wanted so, in the end, I decided to start a new library from scratch.
The library is called rackcheck and you can grab it off of the package server. The reference docs should show up on there soon and there are a few examples in the repo. I'm pretty happy with the result so far, but I may end up making some small API adjustments as I use it more so keep that in mind!