Taskade - Make lists, organize your thoughts, and be inspired to get things done. Taskade is a collaborative space for your tasks.
Nova Inbox - Personalize emails in seconds, right from your inbox
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Gmail Mail Merge - Send personalized emails with attachments
Tables by Google - Tables helps teams easily track & automate tasks
InboxSDK - First usable API to write Gmail Apps for 1B active users