For many years, I loved and used Nancy's Notions Pattern Keepers to store patterns. Pattern Keepers had a front pocket for the pattern envelope and instructions and a ziploc compartment for the pattern pieces. Unfortunately, Pattern Keepers are no longer available. I found a source for similar ziploc bags, but they had to be purchased in cases of 1000. I googled and learned many sewers use comic book protectors to store patterns. These plastic bags come in three or four sizes. For me, the silver size (7 1/8" by 10 1/2") works best.
They are nearly the same size as the Pattern Keepers I'm used to so I can keep my patterns in the drawer I'm currently using. They don't have the front pocket to separate the pattern envelope and instructions, but that wasn't a deal breaker for me.
Rather than a ziploc, these bags close with a flap. Self sealing protectors are available, but I use removable color-coding labels to keep the flaps closed. One of these days, maybe I'll come up with a way to use the color coding. Or, I'll buy the self sealing protectors the next time the urge to organize hits me. These bags are readily available at comic book stores. (Midtown Comics is in the midst of New York's Garment District! How convenient is that?) They are also available at Amazon. I bought three packs (100 bags per $5 pack) for $15 at a local comic book store. Very reasonable, although I don't think I'll ever have 300 patterns.
I kept my current pattern storage set up. A few years ago, I built a wooden box in which I store the patterns, arranged by category. I built the box to fit neatly on the bottom shelf of a bookcase. I will not allow myself to have more patterns than fit in the drawer, so my pattern stash is manageable.
The comic book store sold plastic tabbed dividers that I use to separate and identify the categories.
It was a simple task to design and print the labels. I had to cut the dividers down to size to make them fit neatly in the box.
I photocopy the front and back of pattern envelopes and store them in a binder. My long term goal is to make catalog pages for my traced Burda Patterns. When that is done, I will have a complete catalog of traced magazine and envelope patterns.
So, once again, I got inspiration from a sewing blogger. Thanks to Miss Celie and my local comic book store, I was able to update my pattern storage system.