Open source email service with a strong focus on security and privacy
ObjectivePGP is an open-source library for iOS and macOS
Open Source Email App for Android
Email tracker, read receipt and spy pixel blocker plugin, macOS Mail
Open Source Email App for iOS
Open Source Email App for Android (fka K-9 Mail)
Secure email that protects your privacy
Proton Mail Android app
Fast Bayesian spam filter along lines suggested by Paul Graham
Chat Messenger. E-Mail-Client. Websearch. Filetransfer.
Anti-Spam SMTP Proxy Server implements multiple spam filters
eMail is a fork of Interlink for IA-32 i686 with more optimizations.
Gross greylisting server
Email reader for RISC OS operating system.
C library for sending e-mail (with attachments) from C/C++
Remote anti spam utility
Scrip to send mail with attachments
Send Mime and Smime Emails to Any Type of Mail Server