The FPGA used seems to be quite popular in the hobbyist community. If you don't care about the form factor, there exist relatively cheap high-volume ECP5-based boards that have been repurposed to be general FPGA dev boards [1].
[1] https://www.amazon.com/Price-Colorlight-5A-75B-Screen-Receiv...
The only downside of those is that the SDRAM chip is wired with its DQM pins tied low, which means you can't do byte writes to SDRAM - you have to write a full word at a time. That makes it much harder to port existing cores to the ColorLight boards.