Salesforce - CRM software solutions and enterprise cloud computing from salesforce.com, the leader in CRM and platform as a service.
Onesheet CRM - The Simple CRM for Google Sheets
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.
Followup.cc - FollowUp for email is a lightweight productivity suite that keeps your conversations and tasks from slipping through the cracks. Set perfectly timed reminders that arrive at the top of your inbox, right when you need them.
Padlet - Visual boards for organizing anything.
Freshsales CRM - A full-fledged CRM for high-velocity sales teams.