A plugin for Sketch and Adobe XD CC to populate your design mockups with meaningful data.
plugin
Stark
The color-blind simulator and contrast checker for Sketch. Design with accessibility in mind.
jQuery.fracs
“determines the fraction of an HTML element that is currently in the viewport, as well as the fraction it takes of the complete viewport and the fraction of the area that might possibly be visible. It also provides the coordinates of the visible rectangle in document, element and viewport space.”