POP Peeper - POP Peeper is an email notifier that runs in your Windows task bar and alerts you when you have new...
Shift - Shift is the ultimate email client for managing Mail, Calendar, Drive, Slack, Asana, Jira, Evernote, and all your other favourite apps
Mia for Gmail - A desktop email client for your Mac, without a browser !
Checker Plus for Gmail - Displays new emails and the sender's contact photo, get notifications or even listen, read or...
Mailplane - Mailplane is the best way to use Gmail on your Mac. Use an unlimited number of accounts, get new mail notifications, use plug-ins and much much more.
Google Mail Checker - Displays the number of unread messages in your Google Mail inbox.