Schematic diagrams can change depending on the type of outcome being designed.

All of the examples below are templates form diagrams.net.

For web design they could be wireframes.

A version of a wireframe could also be used to design a Heads Up Display (HUD) for a video game.

It could also be a Unified Modelling Language (UML) diagram to show classes and how a program will operate.

Or it could be a network schematic showing the layout of a network.