Brain.

(It works occasionally).

I just open the big box and have a rummage

Although it's generally used for roms and such, I include my hard copy games in my Lunchbox database. You can manually enter in things and pull meta data that way, which I prefer since I keep a lot of manuals, boxes and stuff in cold storage and aren't about to pull it out.

Plus at the end it the day, they're just xml files.

2 systems, putting the games on my shelf with their boxes (disc games and DS games), and for cartridges games, putting their labels out, or using 3D printed stands to show the cartridge art.

Price Charting and a text file for game items that PC doesn't track. I don't really like any of the available options, though, so I'm very slowly building my own system from scratch to track all my stuff properly. (Baldur's Gate 3 is currently interrupting my progress on that.)

Gameye on Android

CLZ Games but I got it before it went subscription.

I personally use VGCollect. I also keep a spreadsheet of all my physical media.