I really like Atom. It has recently been updated to work with current obsidian versions and now works beautifully with canvas boards too.

Minimal theme, without a doubt. It increases customization of the editor immensely, I can hide whatever I don't need, focus mode is neat, and generally it feels not too far from vanilla obsidian experience

Typomagical. I love serif fonts.

My favourites are:

AnuPpuccin

This is my favourite theme at work. Beautiful in dark mode and works perfectly with the Style settings plugin.

Things 2

My favourite on mobile. Simple, fast, and supports a few plugins that I really dig.

I loved Gruvbox from the moment I first tried it, but couldn't live without Things' tasks status, so... I'm using Things as active theme, but I've added Gruvbox's entire CSS as a snippet. Beautiful beast.