Here's a thing we came up with recently.
Some apps are very, very complicated in nature.
They have so many possible paths through them, plotting out user journeys for all page flows would be meaningless due to the amount of complexity baked into the product.
So this is what we have dubbed a 'Traversal Matrix' which will show some of the most common paths through the app.
This way we can potentially narrow down 4000 possible screen views within the app to a 4x5 grid that will show everything from the top level view.