You can find the example mods in your Foundation installation directory, under the mods folder.
This example mod shows the basic structure of a Foundation mod and can be used as boilerplate code for getting started
This advanced example mod introduces the new modding feature from Foundation 1.2.0.
This mod shows how to implement a new taxation function. There are two examples, one that works by registering to an event to trigger the tax and another that taxes over time.
Removed, for now, since modded maps are not supported at this time in 1.10.
This example mod shows the basics of creating a custom map. The example contains a complete example of all the features available for creating maps in mods. More info on custom maps can be found in the corresponding API documentation page.