InStream CRM - Business relationship management platform - CRM alternative
HubSpot CRM - Free CRM software for small businesses.
Onesheet CRM - The Simple CRM for Google Sheets
Bigin by Zoho CRM - Pipeline-centric CRM built and priced for small businesses
Zendesk Sunshine - Open, flexible CRM platform built on AWS
Gmail CoPilot by cloudHQ - Easy CRM: View all past conversations with an email contact