Note! Code and issues are maintained at https://github.com/sba1/simplemail. SimpleMail is a simple to use but powerful mail client. It supports the SMTP, POP3 and IMAP (in a simple form) protocols. Furthermore, among much other features, it is capable of showing HTML mails and can identify spam mails by using a Bayesian filter.
Thunderbird extension for checking grammar using LanguageTool facilities.
NOTE: The project has been moved to GitHub: https://github.com/nuald/thb-gramchecker The old one stays here just for the historical reasons.