I put my bought patterns in a gallon size zip lock bag with the picture facing out. I keep them in plastic shoe boxes and I stand them up like files so I can just flip through them to see which one I want.
I use the gallon bags because I usually have copies of paper piecing patterns or templates that I want to keep together. It is such an easy system. I also have dividers in them to separate mini, wall hanging, table runners, baby, seasonals, crafts etc.
I do the binder system for loose patterns, cut from magazines and freebee give-a-way sheets. I also sort them by the same categories. So easy and accessible, no hunting for that special baby pattern.
peace