Newton Mail - Newton is a fully featured mail client available for Android, iOS, macOS and Windows.
Spamihilator - The free Anti-Spam-Filter Spamihilator removes more than 98% of spam mails before they even get into your inbox.
myMail - myMail is the smart email app for managing all your accounts on iOS and Android.
SpamAssassin - Use this program to "Unspam" your mailbox(es).
Gmail - Gmail is available across all your devices Android, iOS, and desktop devices. Sort, collaborate or call a friend without leaving your inbox.
Spam Reader - Spam Reader is a free anti-spam add-on for Microsoft Outlook.