Played with the toon shader in Godot 4 today.

Simple to set up, delightful to tweak. Might try and create a bunch of 3D-converted-to-2D isometric tiles using it.

Tutorial: https://www.youtube.com/watch?v=ydwhZlSp9k4

Inspired by: Moebius-style 3D rendering tut, Sable