Most tutorials within these docs demonstrate skills using the Standard Tutorial Data Package, which is available in different formats below.
Esri file geodatabase
Geopackage
Standalone datasets (including shapefiles, CSVs, etc)
The tutorials that demonstrate network-related skills, including creating datasets particular to (or required for) network analysis use the Network Data Package in their demonstrations.
Esri file geodatabase
Standalone datasets (shapefiles only)
Any other data sources used to demonstrate skills are listed within specific tutorials.