#2 Cool & useful: Craft Sync
There are countless apps, plugins, and programs out there that claim to boost efficiency and aid in collaboration; and here is one more that is paired with InVision.
Craft is a new prototype platform built for both Sketch and Photoshop, and boy, I am really looking forward to using it. (Bonus: their website is great; easy to navigate and understand.) It syncs fonts, colors, dims, and assets and prototypes can be built entirely in Sketch where you can link the artboards and gestures and preview the actual functionality of the prototype.
Plus, utilizing InVision, teams can easily review and comment without any project management bog down such as basecamp or google sheets.
I have yet to dig into the fully platform, but will be bringing this idea with me to many new opportunities.
Take a look at their full capabilities here.