I have alot of patterns, they just seem to multiply when I'm not looking :).
Have you ever tried putting paper patterns back inside the envelope they come in once you've unfolded them? Impossible. Instead I have a time honoured system for storing them for easy access.
All the cut out pieces are slipped into clear zip lock bags, and I put them with all the instructions and bits into a large envelope. I then write the pattern number and a description of the pattern on the front at the top so I can see it quickly in the bottom draw of my filing cabinet.
I like it, it works great - except when it doesn't.
I had set aside some time to try out a pattern I have that I haven't made yet. But I seem to have put it somewhere else, which I can't find. The moral is that a system only works well if you follow it.