Something else to look for in ADSBx, there are seven companies that have a contract with the USAF to provider fighter aircraft to act as aggressors during training.
HERE is a ADSBx link to the aircraft belonging to all seven of those companies. When using this link, it only shows these contract fighters, not other aircraft. Note the Callsign/tail number and locations and it will help you locate them when looking at ADSBx (without the U turned on, since these are civilian aircraft).
This may not be a complete list, but it is a complete list of aircraft registered to the seven companies with contracts as of Feb 13, 2025.