aerc

aerc is an email client that runs in your terminal. 

▫Edit emails in the built-in tmux-style terminal, which allows you to check incoming emails and link to other topics while you compose your responses.
▫displaying emails in HTML format using a terminal
▫Vim-style key bindings 
▫Support for multiple accounts with support for IMAP, Maildir, SMTP and sendmail transfer protocols.
▫️Efficient use of the network — AERC downloads only the information that is necessary for the presentation of the user interface, which ensures fast operation and efficient use of bandwidth.

Site/Demo: