Opensource

I use Fractal. It's a GNOME app so GTK and native, No idea if it's cross-platform. I went with it cause I was also looking for something that wasn't Electron and also wasn't TUI (since I want to be able to view images normally) and it seemed like the most suitable, fully-featured option.

I use Cinny. It's pretty fast and has enough features for my needs. Its design is a little reminiscent of Discord.

If you’re like me and want a massive desktop client (not a packaged web interface), Nheko is a full featured one that runs very quick and adapts well to run in both small or large windows.

I use Fractal on my laptop.

Element X on my mobile, and fluffychat as the backup for any features Element X is missing.

Hydrogen is really cool, but I haven't used it in a while.

Fluffychat and Schildichat are really nice on mobile, I use Element on the desktop and if you want to use the same app everywhere I recommend simply using Element.

I use fluffychat on Android, but I'm not sure if it exists on desktop

Hard to beat the Element app or its ‘development build’ the Element X app

I'm using Nheko, I know for sure that it works on Linux, I'm using it on my machine, but on the github it lists MacOS and Widnows in the tags, so I figure they are supported. It's a native program written in Qt and C++.

I've used Matrix for a long time, both on desktop and mobile, and although I'd rather be rid of electron Element is pretty hard to beat...

One issue I hadn't foreseen with Element is that it only supports one account. I recently started a new one on a non-matrix.org server, and until I've figured out how to migrate, I use Fluffychat on mobile instead.

Fluffy is real smooth too, but has its quirks that make me kind of long for Element again.