I was inspired by this thing: https://www.thingiverse.com/thing:3124667
I liked the idea of a monitor mounted pen holder but that one wouldn't fit mine. So I combined that with my affinity for honeycomb and voila.
It can hold up to 22 items (not just pens) and your monitor should be at least 267mm tall in order to get full contact, but I'm sure you could get away with smaller.
You might be able to hot glue it to your monitor but i just used these command strips stuck to the side: https://amzn.to/2KdbrkM
Unless you have a larger sized print bed, you won't be able to print it in one piece so I included a split version. I was unable to print the whole thing in one, so I glued it up with super glue.