Zeplin - Collaboration app for UI designers & frontend developers
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.
Abstract - A secure, version-controlled hub for your design files
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Mightytext - Send & Receive SMS Text Messages from your computer. Sync'd with your Android #
Slack - A messaging app for teams who see through the Earth!