A great summary of the current projects:

https://spectrum.ieee.org/tech-talk/aerospace/satellites/how-nasa-will-grapple-and-refuel-a-satellite-in-low-earth-orbit

It looks like DARPA’s RSGS and NASA’s Restore-L will both get to orbit in 2022. RSGS is headed for geosynchronous orbit, while Restore-L will demonstrate its capabilities in low Earth orbit. Both use essentially the same robotic components.