You can give your drywall texture to hide flaws, and give your walls character. Most use joint compound, because it is inexpensive and easy to use. Applying the compound by machine can give you a variety of techniques. There are also plasters and paints that will create layers of textures.
There is one texture called orange peel that is a very light texture. This is done by using a spray machine. You create the texture several ways, the farther you stand away from the wall the lighter the orange peel bumps will be.
You also create texture by hand, with different movements using a trowel and compound. By using the end of the trowel will also create different textures.
Then you have your faux finishes. This is done with plaster and using different colors of paint. Some plasters have what is called mica flakes, giving the wall a metallic look that will glow when the sun or a light hits it.