Drawasaurus - Drawasaurus is an online drawing & guessing game you can play with friends or strangers.
Excalidraw - Excalidraw is a whiteboard tool that lets you easily sketch diagrams that have a hand-drawn feel to them.
Sketcharama - Draw a given word and let the other players guess your sketch.
Line Rider - Build & design simple sledding courses
Drawception - The browser-based party game that combines the telephone game with drawing! Hilarity ensues.
Drawisland - This website is an online drawing tool where you can create nice draws and animate images too.