Blender's Grease Pencil is Quickly Becoming an Amazing 2.5D Animation Tool - Lesterbanks
Mini Tutorial: How to quickly create grease pencil outlines with nice variation in thickness/opacity for a bit more complex geometry by Luamono (details in the comments) : r/blender
Introduction to Grease Pencil in Blender – Overview, the Draw Tool and Strokes - Cartoon Cocktail
Blender 2D Animation: Get Started with Grease Pencil | All3DP
blender grease pencil and cycles tutorial for abstract shapes and animations Archives - Lesterbanks