High Sierra for me, since it's the latest that would've been able to run any recent NVIDIA GPUs (assuming NVIDIA stayed dedicated to releasing Web Drivers).

The lack of Nvidia support is a major bummer. My KDE desktop at home is configured to look identical to Mojave (albeit with a different color palette and a dock integrated with the menubar), just so I can pretend like I'm living my dream...

Same here. Most things still work well for me, so my plan is to stick with Mojave until I get an M2 MacBook Air or similar next year.

Me three. And I can't jump ship to Apple's arm chips until they permit x86 virtualisation/emulation sensibly.

Me too. I'm still running Mojave on my 2014 iMac 5k!