Maybe this is obscure enough: I used Debian PPC on an old Apple PowerBook G4 back in 2011 to get me through my last semester of community college. My main laptop had finally died (The CPU had overheated, it was an old hand-me-down that barely ran XP before I loaded linux on it, and its fan had always ran hot). I found the PowerBook on ebay for 30 bucks and decided, after 10 minutes of research, to give it a shot. Of course, MacOS on it was a no-go, as it no longer got updates and most software for MacOS was no longer packaged for PPC. It was my first experience using a different/non-mainstream architecture, and it was rough.
The main things I needed, like Firefox and Libreoffice, worked well enough. I got gameboy and N64 emulators working, which was enough gaming for me at the time. My main issues were getting Flash to work just so that I could use one website our college used for one of our classes. I remember spending hours trying to get a third-party Flash plugin working (I think it was called "pepper" and having all kinds of trouble with it. I also remember just wanting to watch a movie or TV show in VLC, and although VLC worked like a champ, there were some formats/codecs that would just lag hellaciously on it, and when I researched, the answer I found was that they just didn't play nice with PowerPC architecture (or more precisely, the drivers for the onboard graphics for this PowerPC cpu... some combination of it all) and that nobody really wanted to work on the issue. Because hardly anyone was using PowerPC on their regular computer by then.
Every time I went to install something, there was a 50/50 chance that it wasn't available in the repos. I'd hear about new software coming out - the linux community seemed to really be growing then, and ElementaryOS was taking off and with it, a lot of modern-looking linux apps and stuff built on Electron was coming out - but it was usually not out there for PPC. I couldn't use Spotify, I don't even think the web version worked. I couldn't play Minecraft (lol I think the laptop would've died if I'd even attempted that). I'd grown fond of Sublime Text Editor (look, i've grown up a lot since then) and it wasn't available. I was basically limited to FOSS apps that someone, anyone, had been kind enough to build and put in the repos for my silly little dying architecture. Or FOSS apps that I was brave enough (with my limited linux know-how at the time) to try to compile (I think I compiled mupen64plus for it? I think that was the only one I had to do)
So yeah, it was a pain. But mostly you could use regular GNU/Linux with your core apps and any FOSS stuff without issue.
Oh, and Youtube didn't really work, until they switched to the HTML5 player. Then it worked, but would lag on any resolution over 480p.
I upgraded to a Thinkpad X60 that summer when I finally landed a job and to date, that Powerbook is the worst computer I ever owned. (I didn't mention them since this is a post about Operating Systems, not hardware, but it had hardware issues: it was heavy, the screen flickered if it wasn't at a certain position, it got incredibly hot when charging, and the fans were noisy as hell).
I still think it's fun to run linux on something other than x86 - I play around with ARM linux on other devices, including Ubuntu Touch and postmarketOS on an old phone. But for my desktop linux experience, I think I'll stick to x86 from here on out, thank you very much.