Sketch-Draw & Paint is one of the free drawing apps for Android that has over 50 million downloads. It brings a fun drawing and photo editing experience to anyone regardless of their skills. Along with multiple brushes, pens, and pencils, it offers several stickers which you can superimpose on your images. You can build advanced sketches with layers, zoom to paint fine details and also backup and sync your drawings to multiple devices. Moreover, it includes options for an eraser, ruler, background selector, undo/redo buttons, export or share images, etc.