Flowpad is a lightweight modern drawing app. It has a wide variety of tools from pens and highlighters to rulers and grids.
Some of the features of flowpad include:
Save ink to continue editing in other apps.
Save as .png .jpg .jpeg .bmp .gif .tiff .jpegxr .gif with embedded Isf or .Isf format.
onscreen color picker
Advanced color picker.
And much much more...
This app has touch, pen and mouse input included.