CiviCRM - A Constituent relationship management for the Civic Sector
Zendesk Sunshine - Open, flexible CRM platform built on AWS
Odoo CRM - Open Source CRM
Crmble - Easy peasy crm for Trello
Salesforce - CRM software solutions and enterprise cloud computing from salesforce.com, the leader in CRM and platform as a service.
InStream CRM - Business relationship management platform - CRM alternative