Mailspring is for people who deal a lot with customer support.
The only downside I can see is that it will require a lot of manual configuration if your email provider is not Gmail. Apart from this, it also offers additional features like spam filtering, email rules, email search, and GPG encryption, and so on.
You can also use Sylpheed via Termianl if you love coding. However, to configure it will be difficult. So, you will find a lot of hotkeys like Ctrl + M to send a new message. Sylpheed is geared more towards users who love to work with their keyboard. It can easily handle large amounts of data. First of all, it is completely developed in C which gives it a massive performance boost over other email clients. It has the same minimalist user interface design with a large set of features. Sylpheed is based on avoiding the shortcomings of Geary email and Pantheon. Geary is geared towards users who rarely use emails and don't need additional power features.
Geary is the most minimalistic email client on this list. It is a good choice for people coming from Windows and other operating systems. Wavebox is geared towards users who use services from different developers like Gmail, Slack, Trello, etc. All-in-one messaging app with GSuite, Office 365 apps, etc.
The pro version starts at $4 per month, which removes that limit and offers additional features like support for extensions, cloud backups, and custom web apps. The deal with the free account is that you can only use two Gmail accounts at a time. Besides Gmail, Wavebox also enables access to other GSuite applications such as Hangouts, Google Docs, Google Sheets, Google Drive, etc. It is a web aggregator that presents the website in an application format. Wavebox isn't exactly an email client, but it's an all-in-one messenger app that lets you use GSuite and Office 365 And many other web applications under one cover. If you use the same, follow These configuration instructions for an IMAP account و POP3 Configuration Instructions. I use GSuite, so most of my email configuration is simple and straightforward. After a lot of research and trying dozens of email clients, here is a list of our top picks of the best email client apps for Ubuntu. I've been using Microsoft Mail on Windows because of its great integration with other Microsoft products like Sticky Notes, To-Do apps, etc., and for a long time, I've been looking for an alternative on Ubuntu. also, the list is not in any particular order.
There will be many features not listed here, such as basic features like – trash, archive etc.
To clarify: Features information is collected from their official websites as it is displayed there.