As you can see by the simple add-in that you wrote today, there's a lot you can do with add-ins. The next step in add-in development is to study the other objects that you can work with in add-in projects and the EnvDTE namespace.
To start becoming familiar with those objects, search Dynamic Help for the various objects that you can interact with. They might include
CommandBars object
OutputWindow object
TextWindow object
TaskList object
CodeDom namespace
Each of these objects gives you access to the IDE. CodeDom is a super-powerful namespace that helps you create methods to add language-specific code to the Code Editor. To see how you would look up the TextWindow object in Dynamic Help, Figure 17.15 is an example of searching for the TextWindow object.
Some useful add-ins that I can think of are
Backing up your project to another location on the network
Zipping and emailing a project or a project file to another developer
Analyzing the code in your project to create custom help files
Accessing code in a SQL Server code library, which you're going to build in the exercises later today
18.118.0.248