Thank you bartv42!
PublishPress is the plugin that Automattic recommended as an alternative, and it is the closest one to matching Edit Flow’s features. It has 7,000 active installs and is used by companies, non-profits, educational institutions, magazines, newspapers, and blogs.
In the free plugin, PublishPress provides an editorial calendar, notifications, editorial comments, custom statuses, content overview, and the ability to create custom metadata for posts. Its creators also offer commercial add-ons for things like a content checklist, Slack notifications, multiple authors, WooCommerce checklist, and more.
Since PublishPress is actually a fork of the Edit Flow plugin, users can migrate seamlessly from Edit Flow without losing any data or settings using the plugin’s built-in migration utility.