Zeplin - Collaboration app for UI designers & frontend developers
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Abstract - A secure, version-controlled hub for your design files
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Mightytext - Send & Receive SMS Text Messages from your computer. Sync'd with your Android #
Nuclino - Nuclino works like a collective brain, helping teams bring all their knowledge, docs, and projects together in one place. It's a modern, simple, and blazingly fast way to collaborate.