InStream CRM - Business relationship management platform - CRM alternative
Onesheet CRM - The Simple CRM for Google Sheets
Freshsales CRM - A full-fledged CRM for high-velocity sales teams.
Zendesk Sunshine - Open, flexible CRM platform built on AWS
Gmail CoPilot by cloudHQ - Easy CRM: View all past conversations with an email contact
Copper - Copper (formerly ProsperWorks) is easy-to-use customer relationship management for small businesses. Capture contacts and sales leads direct from Gmail with our simple CRM.