My go-to for drawing with a tablet. 2D illustration program available on both desktop and mobile platforms with identical features, which is pretty unique. It has a powerful brush engine similar to Photoshop. Also supports HDR.

If you aren't doing CAD or simulation, I would defend Blender as the best way to do all things 3D. Hugely compatible and featureful. Regularly updated and very large community for support and plugins.

Free and open source vector graphics editor. It is to Illustrator what GIMP is to Photoshop. Well suited for print and web graphics, like all the icons on this page. Best for things where you are going to reuse, adjust, and adapt drawings.

Free and open source image editor. It is a reasonable alternative to Photoshop for all desktop platforms, but lacks modern advanced features.

Specialized for game sprites, including animation and sprite sheets. Fun aesthetic and extensible.