As someone else mentioned:

Helion Energy: Located in Everett, Helion is developing a magneto-inertial fusion technology and has announced plans for the world's first fusion power plant in Washington State. They have also secured a significant investment and a power purchase agreement with Microsoft for electricity from their fusion plant.

Zap Energy: Also based in Everett, Zap Energy is focusing on developing affordable, compact, and scalable fusion energy technology. They are working towards a commercially viable fusion energy solution and have received visits from state leaders to witness their progress.

Avalanche Energy: Avalanche is planning a facility in Eastern Washington for commercial-scale testing of radioactive fusion technologies, according to GeekWire.