On Windows, my absolutely vital stuff on the gaming rig are:
Discord
Firefox
Keepass - KeepassXC in my case, but that’s because I also use it on other OSes and well, same UI; otherwise on Windows itself I’d recommend the actual Keepass.
MPC-HC, a media player that has a tiny install size and easily outperforms VLC without even breaking a sweat
On Windows, my absolutely vital stuff on the gaming rig are: