Painting them white to match the ceiling and walls helps camouflage them.
Why yes, even white they look pretty good from here, cant say camouflaged though because 1st thing I focused on. .
But I thought you were talking about the pair supporting the door...
Universal in appearance because they are-if rafters exposed could block for single down support. But no limit to what you could use to replace, round or square tube, folded angle, welded link chain or drive chain, welded tools, gears. Wrap with rope if into nautical, twisted steel, hmm woven tri-twisted bar , probably get pretty creative with round bar. Beaded aluminum panels--old machine butterfly covers. Depends on what your into that might look good in 'your' garage.
Though I dont have a finished garage, I cant say I think waste of time. Im routing some wood pieces to cover an exposed piece of sheet metal channel that I only see when using drill press-kinda funny once we focus on something that otherwise doesnt matter and then hard to ignore.