Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Pipedrive - Sales pipeline software that gets you organized. Helps you focus on the right deals, so easy to use that salespeople just love it. Great for small teams.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Zoho CRM - Omnichannel CRM for Businesses of all sizes
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
Freshsales CRM - A full-fledged CRM for high-velocity sales teams.