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
• Playnite, a multi-library game launcher.