If you right-click on a folder in the folder list (left hand side), a menu comes up and you can select “Add to Favorites.” Your Favorites folders will be listed at the very top of the panel. So, yes, eM Client has that feature too. 
If you right-click on a folder in the folder list (left hand side), a menu comes up and you can select “Add to Favorites.” Your Favorites folders will be listed at the very top of the panel. So, yes, eM Client has that feature too.