Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Mailwasher - Over 8 million people use MailWasher as their spam filter
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
SPAMfighter - SPAMfighter and Microsoft have built the strongest and most effective anti spam filter for Outlook, Windows Live Mail, Outlook Express & Thunderbird
Plivo - Plivo simplifies your customer engagement.
Spam Reader - Spam Reader is a free anti-spam add-on for Microsoft Outlook.