Removing Old Trackers Entries From SteamVR

You can find the list of trackers at the bottom of the SteamVR config file steamvr.vrsettings in the SteamVR config folder (which can generally be found at C:\Program Files (x86)\Steam\config\steamvr.vrsettings).

The list will look something like this:

"trackers" : {
   "/devices/SlimeVR/human://LEFT_FOOT" : "TrackerRole_LeftFoot",
   "/devices/SlimeVR/human://LEFT_KNEE" : "TrackerRole_LeftKnee",
   "/devices/SlimeVR/human://RIGHT_FOOT" : "TrackerRole_RightFoot",
   "/devices/SlimeVR/human://RIGHT_KNEE" : "TrackerRole_RightKnee",
   "/devices/slimevr/human://CHEST" : "TrackerRole_Chest",
   "/devices/slimevr/human://LEFT_FOOT" : "TrackerRole_LeftFoot",
   "/devices/slimevr/human://LEFT_KNEE" : "TrackerRole_LeftKnee",
   "/devices/slimevr/human://RIGHT_FOOT" : "TrackerRole_RightFoot",
   "/devices/slimevr/human://RIGHT_KNEE" : "TrackerRole_RightKnee",
   "/devices/slimevr/human://WAIST" : "TrackerRole_Waist"
}

You can remove whatever entries you no longer want, making sure you keep a comma at the end of each line except the last one, for example:

"trackers" : {
   "/devices/slimevr/human://CHEST" : "TrackerRole_Chest",
   "/devices/slimevr/human://WAIST" : "TrackerRole_Waist"
}

Or you can remove all the trackers like so:

"trackers" : {}

Now when you start SteamVR, you should no longer have those trackers showing up in the list.