Reproducible Set - You can buy a reproducible set if you think you may need minor changes made to your home plans. You can make copies from this type of home plan, but you are not allowed to build more than one home from these type of plans without a separate license.
Having been in the business for more than 30 years, we have seen a large number of house plans which looked good at first glance. However, upon closer examination, many of these plans were found to be lacking large amounts of needed information. If a house plan is not easy to navigate or is not thoroughly detailed, then the builder is left to guess at the designer's intentions. This often means that he will "pad" his bid to make sure that he covers any unknown construction costs that may arise.
On the other hand, stock house plans are substantial past drawn designs by a skilled designer or architect ideally of a specific purpose or general use. The question is, why choose a stock plan over a custom drawn plan? It all amounts to various reasons that are discussed below.
There are dozens of other house plan style categories, such as A-Frames, Mission, Contemporary, Southwest, and Tudor to name just a few. A web search for house plans yields a mind blowing number of searchable sites. Most of these allow you to search for house plans, by style, number of bedrooms, baths, with or without a garage, or by sq. ft. of living space.