Decorator's tape is a useful tool for getting the best finish when it comes to how to paint a room, but it can also be used to create interesting paint effects on your walls and more.
Tape can be used to mask out areas for a color blocked scheme. For example, while you could even use tape to create stripes or a grid-like design too. Many people have found tape useful for angular, geometric wall designs, though these have fallen somewhat out of fashion for more organic shapes, which would need to be painted freehand.