The color-blind simulator and contrast checker for Sketch.
Stark is easy to use and simple to include in your day-to-day design workflow.
Doesn't measure contrast on symbols with color overrides.
Overall a fantastic tool. As a designer, you can seamlessly integrate it into your design process without introducing complexity. I have included this tool to my team workflow while leading UX team at HBO Latam and my company RefineAI.Alberto Orsini has used this product for one month.