RISC-V

The leading no-royalties options as of 2020.

China has been a major RISC-V potential user in the late 2010s, since the country is trying to increase its semiconductor industry independence, especially given economic sanctions imposed by the USA.

E.g. a result of this, the RISC-V Foundation moved its legal headquarters to Switzerland in 2019 to try and overcome some of the sanctions.

Leading RISC-V consultants as of 2020, they are basically trying to become the Red Hat of the semiconductor industry.

Risky name with the Si prefix, too close to SiFive. Both a reference to silicon no doubt, but still. If they stick they will one day rename.