Airmail
An email client that allows you to create OmniFocus actions that reference emails, manually or automatically using rules.
Dispatch
Quickly process your emails and take action when you're on the go. Built-in OmniFocus integration allows you to conveniently create OmniFocus actions that reference your emails.
Drafts
Quickly and conveniently and capture text and then send it to OmniFocus and other destinations through the use of flexible, customizable actions.
Fantastical
An alternative to Apple's Calendar app for Mac and iOS that provides enhanced functionality, a natural language interface, and OmniFocus integration (Mac).
IFTTT
IFTTT (If This Then That) is a free web-based service that can automatically trigger the creation of actions in OmniFocus based on a wide range of conditions.
Launch Center Pro
Launch Center Pro can be configured to provide quick and convenient ways to create and access OmniFocus tasks on iOS.
Mailplane
An email client that combines Gmail's web interface with a slew of additional features, including integration with OmniFocus.
Postbox
An email client for Mac and Windows that is speedy, customizable and extensible. The Mac version includes native support for OmniFocus.
Spark
A polished email client for Mac, iPhone, iPad, and Apple Watch with a focus on email prioritization and support for teams.
TaskClone
Use Evernote to take notes and to capture action items. Then add a tag to the note and TaskClone will automatically create an OmniFocus action for each of your action items.