A fairly common visualization type that is severely underappreciated is the seating chart. The visualization is basically a map showing the placement of seats relative to the main attraction.
Seating charts aren’t like other maps. They have unique requirements and show unique information. Typically, seating charts are encountered during a ticket purchase process, but they also pop up at weddings and in classrooms.
The goals of seating charts depend somewhat on the venue. For stadiums and theaters, they aim to show what your viewing/listening experience will be like. Typically, they are color coded based on ticket price, an important factor when you are trying to balance your experience with your means.
Similar to floor plans, they often need to show several levels. Usually this is accomplished through showing multiple plans for each view, but sometimes there are “3D” views that get the same information across in a single diagram.