Board game paper minifigure stand

As I started playing table-top RPG games with kids (in the pictures it was Hero Kids), I found that the paper stand-up minifigures need some sort of a stand. Small folded pieces of printer paper are just too light to stand still - every wind blast, no matter how light, blows them away.

I'm sure there are a lot of stand things out there, but most of them are for cardboard figures, 1mm thick and more, and most of them are have rectangle stands.

My design features:
* narrow slot - suitable