Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Sortd - Rated the #1 App for Gmail
Prodeus - Track your time learning on YouTube to earn your free degree
KanbanMail - A Kanban board for your emails.
Todo - Todo is a to-do and task list app.
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.