Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.
Callpage - Turn website visitors into sales calls. Use CallPage and provide immediate free phone callback to your leads in 28 seconds.
BotStar - BotStar | Engage Customers Online with Live Chat & Chatbots
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Telegram bot API - The Bot API allows you to easily create programs that use Telegram messages for an interface.
Novocall - Novocall converts web visitors into sales calls in seconds.