3D Tools
Female/Male Head Lighting Tools
These tools allow you to position lights around a low resolution head to use as a reference for drawing/painting. They’re not super intuitive, but potentially useful. You can pause the video to stop the movement of light and still be able to rotate the head.
Magic Poser Web
A basic, but potentially helpful free tool for drawing reference. You can pose multiple 3D figures and change the camera angle.
SketchUp
A 3D modeling app that is popular among artists. Requires you to sign-up for an account, but there is a free option.
Image Editing Programs
Affinity Suite
Reasonably priced alternatives to Photoshop, Illustrator, and InDesign.
GIMP
GNU Image Manipulation Program, or GIMP, is a free image editing program that will work as a Photoshop substitute. Available for Windows, Linux, and Mac, and more.
Krita
Free, open source Photoshop alternative for Windows, Linux, and Mac.
Paint.NET
Free Photoshop alternative for Windows.
Miscellaneous
Coolors.co
A tool for creating color schemes. Hit the space bar to generate a random pallet. Click a color to lock that color or use the various buttons to customize your pallet.
Paletton
A tool for creating color schemes. Has buttons for creating random pallets or allows you to manipulate various settings yourself.