Email tracking for Gmail — Mailtrack
Filepicker.io | File Upload Plugin for Web and Mobile
Gmail Dot Trick Generator
Mailalert - Free Email Tracking
MailTracker - Free email tracking for Gmail • Hunter
Mailvelope: PGP for Gmail & Webmail
Moo.do
Pigeon for Gmail - Powerful CRM and automation suite for Gmail.
Saleshandy - A cold email outreach platform to get more conversions
Scheduled sending and email reminders | Boomerang for Gmail
Unroll.Me
Vtiger for Gmail - Chrome Web Store
Which Gmail Tab? - Litmus
Yanado - Task management inside Gmail.