Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Chatib - Chatib is an online chat room where you can meet and chat with new people, make them friends, or even data them online.
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Element.io - Secure messaging app with strong end-to-end encryption, advanced group chat privacy settings, secure video calls for teams, encrypted communication using Matrix open network. Riot.im is now Element.
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
Kandan - Open Source private chat server. Your own private Chat server in minutes, plus additional features.