Sketch Talk - A community for Sketch users of all skill levels
SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters
SketchCasts - A weekly screencast, all about how to use Sketch
DeskAlerts - Send alerts to any corporate device: PCs, phones, tablets, etc.
Sketch 101 by Designlab - Learn Sketch in this free course w/ downloadable templates
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.