Zeplin - Collaboration app for UI designers & frontend developers
Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
Abstract - A secure, version-controlled hub for your design files
TeXstudio - TeXstudio is an integrated environment for writing LaTeX documents.
Mightytext - Send & Receive SMS Text Messages from your computer. Sync'd with your Android #
LyX - LyX is a document processor.