There are a crap-ton of helmet stands out there.  Most of them, IMHO, are not something I'd want on my display shelf.   This is my (very) simple design I use to display my helmets.

With these fast-printing parts, you can have a sturdy/stable stand that will fit any helmet.  The top disk holds helmets firmly in place allowing you to adjust the angle/position to create the ideal display.

Its robust design doesn’t necessitate glue. However, if you plan to move them frequently, I suggest using glue to make them easier to carry.  

It can hold the heaviest of helmets… shown below with a real ‘American Football’ helmet (no glue used in the picture below)

Not all helmets are the same size. Sometimes you need a taller stand to handle the largest of helmets.  Print the post sections you need for that perfect fit.

Most of us put a lot of work into our bucket-building-obsession, don't settle for a plastic-3D-looking stick to display it on.  Make your helmet the focus, not what it is being held with.