Free Code Camp - Learn to code by helping nonprofits.
Sortd - Rated the #1 App for Gmail
W3Schools - W3Schools is a web developers information website, with tutorials and references on web development...
KanbanMail - A Kanban board for your emails.
Codecademy - Learn the technical skills you need for the job you want. As leaders in online education and learning to code, we’ve taught over 45 million people using a tested curriculum and an interactive learning environment.
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.