Opera Mail is made by the developers of Opera web browser and supports unlimited numbers of email accounts to be added on its interface. Supports IMAP and POP3 protocols, adding new accounts is pretty easy and is able to suggest settings automatically.
It has a modern interface with tabs, you can switch between emails easy. Allows to assign different colors and tags for messages
1. Pretty intuitive interface
It has a modern design, at the first view it has many links, but they may be helpful if you love to customize the program. You can adapt it through its settings to look like you need.
2. Add new account easy
Enter email address, display name and password and Opera Mail will detect the settings. You can choose IMAP or POP3 as protocols.
3. Custom signature
Is easy to add and customize a signature that will be automatically added to your emails. Supports HTML tags to add links in signature, a web address for example.
4. HTML formatting when composing
You can compose emails as plain text or use HTML formatting to choose custom fonts, colors, align text, insert links, pictures or other HTML code.
5. Mark emails with colors
You can assign labels to each email. Each label has a tag name. This may be useful to sort email messages from your Inbox later, especially if you have many of them.
6. Tabbed interface
All messages are open in different tabs and you can switch between them with a single click of your mouse.
7. Different layouts
Is easy to choose or to change the layout or arrangement of the interface, with a few clicks.
8. Just a few General options
At general options i have expected to find settings for spam filtering, security etc, but there aren’t.