Adobe's answer to Sketch: a combo of design and prototyping power-packed into the same interface. Currently in beta, but rapidly evolving and preparing for a bigger release. Anima has been creating a suite of great Sketch plugins, the most recent of which is Launchpad.

Thanks to True North Podcast for being a sponsor of the monthly UX Tools newsletter. Like I've said before, Figma is gunning to be the Google Docs of design. Because it's still in Beta, some of their highly touted features (like live-collaboration) have yet to reach customers.