Current-ish stuff
HDRTray - Windows Notification Area icon to show and change HDR status.
Useful if you quickly want to check the current setting, maybe because it might been changed automatically by some applications, or maybe just because you're forgetful.
Also allows quick toggling.
Old Stuff
SteamLibrarian - A tool to manage a Steam library distributed over folders on multiple drives, see how much space a game takes up, and move it between folders.
Mostly superseded by Steam providing "move" functionality itself.