I like to keep a number of X-Acto knives set up with different blade styles but I don't like them rolling around with unshielded blades and I don't like having to remove, and later replace, a slide-on scabbard every time I want to use one.
I used a 59 cent clear plastic screw-top jar from the dollar store and attached a circle of wood cut from a 2 x 4 to the inside of the lid. This provides the needed thickness to keep the knives vertical. An array of 3/8" holes drilled with spur drills accepts almost any of the available blade designs. A circle of thin wood on the bottom of the jar prevents the sharp blades from punching through the light plastic.
Now I move the knives as a unit without endangering my fingers and see the blade I want easily.