The open tools also work on ECP5, which goes quite a bit bigger than the Cyclone 10 chip on the Arduino and is also pretty cost effective. In fact it's big enou

The open tools also work on ECP5, which goes quite a bit bigger than the Cyclone 10 chip on the Arduino and is also pretty cost effective. In fact it's big enough that you can usually dispense with the separate microcontroller - I built a ulx3s which can boot Linux on the ECP5-85.