I haven't used them myself, but these boards look awesome, and they are supported by an end-to-end open source toolchain: 1. https://www.crowdsupply.com/1bitsq

I haven't used them myself, but these boards look awesome, and they are supported by an end-to-end open source toolchain: 1. https://www.crowdsupply.com/1bitsquared/icebreaker-fpga https://www.crowdsupply.com/1bitsquared/icebreaker-fpga 2. https://www.crowdsupply.com/radiona/ulx3s https://www.crowdsupply.com/radiona/ulx3s 3. https://groupgets.com/campaigns/710-orangecrab https://groupgets.com/campaigns/710-orangecrab