CS183B - Startup Class - Stanford class taught by Sam Altman & guest speakers
SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters
YC Startup Class - A live, one-hour class by Sam Altman on Platzi
DeskAlerts - Send alerts to any corporate device: PCs, phones, tablets, etc.
Google Classroom - Learning management tool by Google
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.