On Mac I use Ulysses. I hate that they switched to a subscription, but it's still the best Markdown app on the platform.

On Linux I use typora (previously caret when it basically shut down). typora and caret are built on web technologies and cross platform.

Oh Android I used to use and recommend JotterPad, but they've disgraced themselves and moved previously paid features (which I bought!) to a subscription, so I don't have an Android app anymore :(.

Notable is great and open source.

https://notable.md/

I've been happy with Markdown Edit. As a native app with an embedded webview, it's just a bit snappier than most of the Electron-based Markdown editors I've tried.

https://mike-ward.net/Markdown-Edit/

i like using marktext. its a single document editor instead of a note manager like notable or evernote, but it also has a sidebar where you can add a folder.

https://marktext.app

im not sure if its actually native though or whether its using electron... but i think ghostwriter is. tried that for a while. pretty much the same as marktext just without a sidebar

https://wereturtle.github.io/ghostwriter

IA Writer has a Windows version.

Mark Text