Available on both iPad and iPhone, Animation Desk allows you to create animations, drawing cartoons or just some light sketching when you're on the go.
Pro Quick sketch
Great for light sketches, and some drafting for your animation.
Pro Photoshop compatible
Supports PSD file import/export, can export your draft to Photoshop easily for further works.
Pro Free to use
Some features may require purchases, but the app free as is and works fine.
Pro Works on different platforms
It supports almost every major platforms, so working on iOS and Android devices is not a problem.