As a reminder the NGS has custom CORS data files available for download that include GNSS (GPS + GLONASS) data. You can access this through their User Friendly CORS (UFCORS) website.
How do I know which base stations are GNSS capable?
The CORS map legend indicates base stations that include both GPS and GLONASS data (GNSS). The boxes are color-coded for the epoch rate of the base station.
What Trimble Mapping and GIS receivers are GNSS capable?