Shortcuts
Another feature from iOS 12, Siri Shortcuts will extend the ability for users to create custom voice actions to run various tasks on their Mac as well.
A macOS version of the standalone Shortcuts app is also expected to arrive, and while this will almost certainly overlap with Automator workflows, it will provide an interface that iOS users will be more familiar with, and of course ensure that as iPad apps find their way to the Mac via Marzipan, their accompanying workflows can make the transition as well.