Inkscape is a free and open-source vector art editor that uses Scalable Vector Graphics (SVG), allowing your artwork to be scaled to any size without losing quality.
MediBang Paint is a versatile and free digital painting and manga creation software available on multiple platforms, including Windows, Mac, iPad, iPhone, and Android.
Blender is an all-in-one free and open-source 3D modeling program that allows you to model, sculpt, rig, animate, run physics simulations, render, composite, and even draw and paint all in one application.
FireAlpaca is a free digital painting software designed for both Windows and Mac users, featuring regularly updated brushes, comic panels, animation tools, mesh transform, 3D perspective tool, and more.