iPhone: Microsoft updated its Outlook iPhone app today, which happens to be one of the best email apps on iPhone, with a new feature that links the app to a number of third-party add-ins.
At launch, Outlook has a number of different add-ins: Dynamics 365, Evernote, Giphy, Nimble, Smartsheet, Translator and Trello. Once you enable them, you can then use those add-ins while composing or reading email. For example, you can have the translator add-in translate text in an email you receive without leaving the app, or you can send an email over to a Trello board.
Essentially, they're like miniature, officially sanctioned extensions. Unfortunately, these add-ins are live first for Office 365 users, with Outlook.com users coming next. It is a handy set of features though, so hopefully we'll see it supported for other email accounts soon.