Chaz Hutton has a great post on Medium with some quick tips on how to draw comics and the section on emotions caught my eye:
You should probably learn how to do emotions. Those are easier than you think and can be achieved through the clever placement of lines. You can go from worried, to surprised, to angry all with some little flicks of your pen…
He demonstrated a few simple ones and in Mike Rhode’s Sketchnote handbook he gives a few more easy emotions:
I love that all these are really just simple lines and shapes that anyone can do, and what makes a good comic is a narrative, not the actual drawing.