Addons extend the functionality of Slider Revolution, adding new controls to the module editor [?]
The "Module Editor", also known as the "Visual Editor", is an interface used to create & modify modules.
It's through this interface you can add various types of layers to your modules, as well as animation and special FX. and allowing you to do extra things with your design.
For example, using the particle addon you can create effects such as falling snow, and using the distortion addon you can create shimmering effects such as simulating being underwater.
There are dozens of addons available, all included with the full version of Slider Revolution.