Select text in any Mac app and PopClip pops up with instant text actions. Install the OmniFocus extension and you'll be able to send selected text to OmniFocus.
Hookmark for macOS makes it possible to link your OmniFocus projects and actions to almost anything, including files, folders, notes, websites, and emails. Having what you need within easy reach accelerates the process of getting things done.
Create OmniFocus actions, action groups, and projects more quickly and accurately by defining TextExpander snippets for frequently typed words and phrases.
IFTTT (If This Then That) is a web-based service that can be used to automatically trigger the creation of OmniFocus actions based on a wide range of conditions.
Using Hazel for Mac and AppleScript or Apple Shortcuts, actions can be automatically created in OmniFocus for Mac as files are moved to specific folders.