Paint Effects includes hundreds of saved brushes called preset brushes. These are stored in the your mayapath/brushes folder. You can also create your own preset brushes and store them either to a shelf or to a Visor subdirectory.
When you select a preset brush, its settings are copied to the template brush where you can tweak them before painting your stroke.
If you do not select a brush preset before painting, the next stroke you paint uses the current settings for the template brush.
To open the Visor, select Window > General Editors > Visor, or in the Paint Effects panel, click the Get Brush button on the toolbar. 
If you select the preset brush in the Visor, the icon becomes highlighted with a yellow border, indicating that the brush settings were copied to the template brush.