The status "In progress" was added to Wikimedia's Phabricator in T288956, and allows us to set that status to show that something is actively being worked on. However, there is one downside to its current setup: When a workboard is sorted by status (such as WMNO-General), tasks that are "In progress" are shown below tasks that are "Open" or "Resolved". This effectively "hides" them from the workboard if there are many open (or visible & resolved) tasks. I think it would be better to give them the highest priority so they are shown at the very top in this view, so that users easily get an overview of what is actively being worked on.
Screenshot: