V12 Data - V12 Data offers rich data sets with verified addresses and emails for personalized marketing campaigns.
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Adobe Audience Manager - Adobe Audience Manager is a data management platform that integrates online and offline data to deliver a unified view of all your audiences
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
Google Audience Center - 3 votes and 6 comments so far on Reddit
Facebook Messenger - Facebook Messenger is a faster way to message.