1) Kiwi

Kiwi has a lot of cool Gmail tricks to make use of, not least the clever way that it lets you access emails from several Google accounts inside the same interface. It’s well worth a look if you have both personal and work-related Gmail inboxes, for example, and you can switch between them with a click.
While the core Kiwi experience is more or less the same as Gmail on the web, it makes a real difference being freed from the browser: Notifications can be handled by the operating system for example, and you can send files to Gmail straight from File Explorer or Finder. Keyboard shortcuts are supported as well.
Icons around the edges of the interface give you access to other Google apps (including Google Calendar and Google Docs), as well as additional Gmail accounts. You can’t try out Kiwi for free, just dirt cheap—personal plans start at $2.75 a month, with more features and options available as you go higher.
Download Kiwi for Windows or macOS, from $2.75 a month.