Topicbox - Put team emails into one centralized, searchable place
Nova Inbox - Personalize emails in seconds, right from your inbox
InboxSDK - First usable API to write Gmail Apps for 1B active users
Dynamically Personalized Emails by QGraph - Hyper-personalized emails for E-commerce
Front - multi-channel inbox service for collaborative teams
Gmail Mail Merge - Send personalized emails with attachments