Top Alternatives to Nylas Mail

Thunderbird is a open source mail client developed and maintained by Mozilla foundation.

Microsoft Outlook is a personal information manager from Microsoft.

Mailbird is a desktop email client for Windows 7, 8 and 10.

Apple Mail is an email client included with the operating systems macOS, iOS and watchOS by Apple Inc.

eM Client is a Windows based e-mail client for sending and receiving e-mails, managing calendars, contacts, and tasks.

K-9 Mail is an open source email client with support for multiple accounts, search, IMAP push email, multi-folder sync, flagging, filing, signatures.

Evolution is the official personal information manager for GNOME.

Postbox is powerful, intuitive, ultra-customizable, speedy task manager.

Mailspring is a multi-platform email client.

Geary is an email application built around conversations, for the GNOME 3 desktop. It allows you to read, find and send email.

The Bat! is an email program for Windows that protects the correspondence and empowers the users to handle large amounts of emails quickly and efficiently.

Zimbra Desktop is an offline client that lets you manage various email accounts in one desktop tool.

KMail is the email component of Kontact, the integrated personal information manager from KDE.

Spark is a fast, smart mail manager app.

Polymail is an email application for OS X and iOS known for its clean interface and additional features atop the Gmail platform.