draw.io - Online diagramming application
Screencastify - Free screen recorder extension for Chrome. Capture, edit and share screencasts. No software download required. Works on Mac, Windows and Chromebooks. Screen RecorderFree screen recorder for Chrome.
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.
Loom - Loom is a screen recording extension for Chrome that gives people the ability to create and share media. Create your own videos using your camera, screen view, and audio. Read more about Loom.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
SketchCasts - A weekly screencast, all about how to use Sketch