Kanban
Kanban is a way of visualising work as cards moving across columns — usually To Do, In Progress, Done — so a team can see what's happening at a glance and limit how much is worked on at once.
It's one of the most widely used tools outside software teams now — customer service queues, process improvement backlogs, even hiring pipelines run on Kanban boards. Knowing it means you can walk into almost any team and understand how work is tracked.
A customer service team is overwhelmed by tickets with no visibility into what's stuck. They set up a Kanban board with a work-in-progress limit per stage, and within two weeks the backlog stops growing, because nobody starts a new ticket until an older one is finished.