Free Sketch UI Kit for Bootflat http://bootflat.github.io/
We've created a Sketch version of Bootflat framework and added some missing elements which are not included in the UI KIT PSD.
To use, simply download the Download ZIP button on the right sidebar, unzip and open the .sketch file. It's recommended to place this file somewhere safe, and duplicate it when you need to create your own layout.
Sketch 3.1+ is required
LICENSEfor more details.