My favorite source for patterns (for my Etsy shop) are estate sales. Typically the estate sale is a treasure trove of patterns sewn for the family over the decades. Not only does it provide a wide range of patterns, but typically it also includes some craft patterns and hand-made patterns cut out of newsprint.
An estate sale purchase was, in fact, how I "fell" into running my Etsy shop. I purchased approximately 300 patterns from an estate sale in my neighborhood. There was no interest in them from other buyers and I took pity on them. :) My neighbor had sewed for her family all her life and her stash included patterns for children, women, and men, and spanned 5 decades or more. What a history of fashion! That was back in 2008, and I continue to search estate sales, as well as other sources, for patterns for my Etsy shop.
This recent purchase is typical example. The mother kept her patterns in a special decorated box (a little worse for the wear).
As expected, the patterns include fashion for all occasions (from sleepwear, to every day, to special occasions) for men, women, and children of all sizes. It also includes a handful of craft patterns, a booklet on crafts, and other hand-traced craft templates.
Also typical are hand-made patterns, like these bodice or blouse pieces. Thrift is often a key element found in estate sales. I love this peek into the historical times of a sewist's life!