This is my current favorite.
I think it gives the most 2D feel.
No base coat, after a matte topcoat, acrylic gouache (paint) was thinned with acrylic paint thinner, panel lining was done with a Gundam Marker panel lining pen and Pigma 003, corner lines were drawn with a Procky (water-based marker), and a matte topcoat was applied as a finish.
Four-stage finish: highlights, molded color, shadow color, and shadow color 2 (just a little).

Pallas Athens | ユッキーさん's Gunpla works