Drip Scripts - Create automated email sequences in 60 seconds
Roundcube - Web-based IMAP email client
Campaign Genius - Send dynamic email content through any platform, instantly.
HEY - Email at its best, new from Basecamp.
Polymail Sequences - Simple, powerful multi-stage email campaigns
Mailo - Mailo is an email client where you can send and receive emails to and from anyone with an email address.