Line of Action — timed figure drawing exercises
SketchDaily — (more) timed figure drawing exercises
Quickposes — free image library and gesture drawing tool for artists
Art Models 360 — rotatable nude models
AdorkaStock — pose reference photos
Pose Search — find reference images of any human pose using a moveable skeleton model
Pose Search — same as above, except uses reference photos from Human Anatomy for Artist
Human Anatomy for Artist — pose reference photos
JookpubStock — pose reference photos
The Pose Archives — pose reference photos
Bodies in Motion — figure and anatomy reference videos/gifs
Shutterstock 3D Objects — rotatable 3D models (inanimate objects)
POSEMANIACS — poseable hands and body
PoseMy.Art — poseable 3D models
DesignDoll — poseable personalized sketch doll (download only)
Figurocity — 3D models to figure draw from
ArtStation - Male Head — lighting reference model
ArtStation - Female Head — lighting reference model
Perspective Grid — moveable perspective grid
Animal Photo Art References Search — find reference images of any animal head at any angle using a moveable animal head model
Muscle Plus — muscular male body reference photos
Photo Reference for Comic Artists
Characterdesigns.com — pose and costume reference photos
Fat Photo Reference — fat body reference photos (requires you to request access)
Height Weight Chart — reference photos of people at different heights and weights
Wikimedia Commons — huge image library (public domain)
NYPL Digital Collections — New York Public Library photo collections (public domain)
Nasa Johnson | Flickr — more NASA photos
Astronomy Picture of the Day Archive
Drawabox — free art lessons
The Dimensions of Colour — everything there is to learn about color
Draw Mix Paint — oil painting lessons
Magma — draw with other people
draw.io — Google Drawings clone
Wigglypaint — Mac Paint–inspired drawing tool that makes your lines squiggly
Shake Art DELUXE — another site for drawing with squiggly lines; this one lets you adjust the speed and intensity of the squiggle
JS Paint — web browser remake of MS Paint
JSKIDPIX — web browser remake of Kid Pix
Cloudpaint — web browser remake of Mac Paint
Photopea — web browser remake of Photoshop
Kleki — online paint tool
Piskel — online sprite editor
Checkbox Painter — draw with checkboxes
HTML Portfolio Template — what i used for my art gallery page!
The Fighters Generation — site dedicated to fighting games
Catland — Louis Wain art archive
Macpaint.org — historical gallery of Mac Paint