To be clear, that's Cataclysm:Dark Days Ahead or CDDA. It's quite removed from the original cataclysm by whalesdev, and is more focused on strict realism. There is also Cataclysm Bright Nights which is closer to the arcadey feel of the original. Both are great and are open source.

Going to submit my probably-not-a-puzzle-game-game: rhythm games. The game tells you exactly what to press and when you're supposed to press it, it's just up to you to actually press the buttons. See: DDR, Rhythm Doctor.

Note that there are rhythm games that have more decision making like crypt of the necrodancer (rhythm roguelike)

Not directly answering your question, but if you haven't already you should take a look at the end of life disaster recovery repo.

Yes, it really is that bad. We have a resin printer at work and it has been banished to a different room due to the resin fumes. The table it sits on is perpetually sticky, and we go through twice as much IPA postprocessing the prints than we use in resin

Cataclysm: Dark Days Ahead. Zombie survival roguelike, forked from the original cataclysm by whales. Also check out Cataclysm: Bright Nights which is a fork of CDDA that makes it more gamey like the original, and less like you're playing 2d arma.

Sunshine and moonlight are open source implementations of nvidia's game streaming protocol they created for the nvidia shield. You can use it to remotely use your computer from your phone, not just for games. But of course the primary application is game streaming. As long as the game can run on the host (sunshine) computer, you can remotely play it on the client (moonlight) device. I've used it to just launch steam in big picture mode and then select what I want from steam.

You have to add them manually, either by url or with the built in search. For example, you can add newpipe by searching sources and checking github as a source to search. It will then show you repos that match newpipe, which usually is the regular newpipe repo and then a bunch of forks of it.

Obtainium isn't for finding FOSS apps, it's for installing them. To find them, you can check out existing repos such as f-droid or izzy, or you can ask around. This post has a bunch of recommendations in the replies

Obtainium lets you install FOSS programs directly from the developers source. You can get updates from the github/gitlab of app developers before they get uploaded to F-droid.

Hyperrogue is not quite a top down hexagon world, it's a top down heptagon world. The premise is that it is a roguelike set in a hyperbolic world, and different regions teach you different weird properties of a hyperbolic space. For example, the crossroads feature an infinite amount of parallel lines and yet there are still forks in the pathway.

Even though it's foss, it is also for sale on steam if you want to support the dev

Lossless Cut FOSS, Crossplatform frontend for ffmpeg. Note that to do it losslessly, it will still be in mp3. If you need to transcode you can do that too, but like others have said you'll probably lose quality.

"Trust me."

I mean, you can grind your own mirrors, how hard could it be? (Spoiler: very hard)