Apps similar to Nextcloud Mail include Thunderbird, which is free and open source. Other options are Betterbird, Microsoft Outlook, Evolution and Geary. There's no shortage of Email Clients like Nextcloud Mail, with more than 25 alternatives for Linux, Windows, Mac, Android and iPad.
MailCode is a desktop mail client for people whose mailbox stopped being an inbox years ago and became an archive. It keeps every message on your own machine, indexes all of it, and answers a search.
Türkiye
Balsa is an e-mail client for GNOME, highly configurable and incorporating all the features you would expect in a robust mail client.
yMail2 is a standalone email client for Windows (and Linux), available for free since 2003. Now with SSL support included so you can use it with Gmail and Hotmail POP3 and SMTP accounts.
Australia
Hylki is a fast, GNOME-native email client with a three-pane layout, unified inbox, and support for OAuth accounts. Fast to open, effortless to read, and private by default.
United States
LeaderSend takes care of delivering your transactional messages and managing infrastructure, while you can focus on your business instead.
Mail and calendar for Linux. Gmail and IMAP accounts, Google Calendar, contacts, OpenPGP and S/MIME. GTK4 and libadwaita, written in Rust.
Navigate messages with zooms and swipes across your messages.
Turn your email into colorful, visual tiles you can explore with your fingers or mouse. Rich 3D visualizations and familiar gestures make TouchMail the fastest and easiest way to keep your inbox clean and keep import.
United States
Convey is an email application built around conversations, for the GNOME desktop. It allows you to read, find and send email with a straight-forward, modern interface.
United Kingdom
