Take a look at the de10 nano. Crazy good board for the price. No OSS tool chain though.
To flesh this out, the de10 is a cyclone V board, so you actually end up with an ARM core/s to play with as well.
Lattice has a line called PolarFire which combines a fairly big FPGA and a RISC-V core, but they're very expensive, so I doubt I'll have my hands on one for a while.
If I ever luck into the big money, I know for sure I'm going to bankrupt myself buying toys like https://www.xilinx.com/products/silicon-devices/soc/rfsoc.ht...
https://core.ac.uk/download/pdf/147963601.pdf