I have a few different methods for storing my rulers.
1- I drilled holes on one side of my cutting table then put in long small bolts/screws through these holes, then mounted my rulers, and finally but a nut at the end to keep the rulers on the bolt/screw. I keep similar rulers together. This is where I keep my secondary rulers, like bias square up ruler and square rulers.
2 - I have a homemade ruler holder hanging from one of the above bolts/screws. It is approximately 8 1/2" wide and 22" long made of cotton fabric but with batting between the layers at the backside. It has 3 separate pockets in the front, each pocket getting deeper. This is where I keep my 6", 12," & 24" rulers that I use regularly.
3 - I have 2 of those circular belt holders hanging from the side of my quilting bookcase that hold irregular rulers. Those that I use only for special projects.
4 - I have a portion of a drawer for my smaller templates and rulers and keep any ruler directions with these rulers.
One solution alone isn't enough for me.
I don't want the rulers to take up table top surfaces so I can avoid clutter ... or the look of clutter.
Works for me.
ali