Based: Will play these games over and over. Most of the stay installed
Couch co-op: For when friends are coming over and I quickly can pull up my selection of playable games
Need to finish: Things I already played at least halfway through, I'll never give up hope booti g them up again but most of the time I just buy a new game when I'm bored lol
Games I am currently playing are at the top of "recent" anyway. And if I am done with a game I probably won't play again, I set it as hidden.
Categories for game series longer than 2 games like Fallout or Elder Scrolls or CoD, the favorites category, one for games that I got free and don't really like but kinda might wanna play again sometime, one category called "Tim Games" because I know a guy named Tim who plays some weird shit so sometimes I get what's on his recent list
I have "all time fave" which are games I keep reinstalling every so often, then I have "installed" vs "not installed"
The category for favorites is just so when I inevitably go to look for a game to install because I'm bored with what I have, it's at the top when I un-check the "installed" button.
I want categories like this, but I already have categories for each franchise. Anything that's related to a franchise goes into a category named for that franchise. Even if it's just a game and its soundtrack. That way, everything for a particular game is kept contained and I know what's related to what. If I have a random "dev tools" installer in my library, I figure out what game it's for (thanks to SteamDB.info and it goes into a category along with that game.
I do have a separate category for simulation games, but only because I love simulators and have tons of them. Outside of that, any attempt to make genre categories has just further confused my library. So for not, I just have hundreds of categories for specific games and their included content and/or sequels.