This is a project by Building SMART to generate example IFC files. Primarily for IFC4 (but not restricted to this schema), it is intended to concentrate on samples and unit tests demonstrating features and improvements in IFC4.
You can find an introduction and explanation of the project here https://www.youtube.com/watch?v=0g3rTPQKONE&list=UU01FBzTNN-umc7w1-MYnABw
It uses the Geometry Gym open source toolkit (MIT License) available from https://github.com/jmirtsch/GeometryGymIFC or nuget to generate the classes and files.
If you have suggestions or requests for further examples, or wish to contribute, then please don't hesitate to get in contact.