If you are looking for examples on how to develop for Dynamo, take a look at these resources below:
These samples are Visual Studio templates that you can use to start your own project:
Third party developers have made significant and exciting contributions to the platform, many of which are open source as well. The following projects are exceptional examples of what can be done with Dynamo.
Ladybug is a Python library to load, analyze and modify EneregyPlus Weather files (epw).
Honeybee is a Python library to create, run and visualize the results of daylight (RADIANCE) and energy analysis (EnergyPlus/OpenStudio).
Bumblebee a plugin for Excel and Dynamo Interoperability (GPL).
Clockwork is a collection of custom nodes for Revit-related activities as well as other purposes such as list management, mathematical operations, string operations, geometric operations (mainly bounding boxes, meshes, planes, points, surfaces, UVs and vectors) and paneling.