I currently use three ring binders, with the sheets in sleeves.
My father had a shelf type thing with many shelves, about 1¼” apart. The entire shelf was about 3’ to 4’ tall. No binders that I knew of, no sleeves. (He taught band.)
We do three ring binders with sheets in sleeves also. It’s the easiest way.
How many different types of instruments are you dealing with? Dad might have 100 different in one of his bands.