I always look for MathJax/latex support with at minimum a live preview pane (split view) and ideally WYSIWYG. By this criterion, MarkText seems to be great. As

I always look for MathJax/latex support with at minimum a live preview pane (split view) and ideally WYSIWYG. By this criterion, MarkText seems to be great. As others said Typora is similar but not OpenSource. Nota is nice but has no side by side preview pane. VSCode + markdown plug-in is good — not sure if it supports math. I also like the Marp plugin for making slides in markdown (it does have math)