draw.io - Online diagramming application
Zeplin - Collaboration app for UI designers & frontend developers
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Mightytext - Send & Receive SMS Text Messages from your computer. Sync'd with your Android #
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
ActiveWords - Auto correct on steroids