The best alternatives to Paintr are Hint.css 2.0, Tilt Brush by Google, and JS Paint. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Paintr?
Hurree— The smarter, simpler way to analyze your data
Blue Sky Paint is a fun way to draw on the sky in augmented reality! - Draw with other users in real-time - See drawings from other users around the world - Take one-of-a-kind photos with your drawings - Leave your mark wherever you go
This app allows you to create a landscape painting in the style of Bob Ross using a deep learning model served using a Spell model server. To do so paint some shapes on the canvas with a set of thematic (trees, mountains, etcetera) brushes provided to you.
PaintCube is web-based 3d texture painting app that allows you to create and export textures for your 3D models, a range of familiar painting tools that let you paint directly onto your models in 3D space allowing a seamless UV workflow