Why do this, since even stock plans cost you at least a couple of hundred dollars each? Because the right stock plans can save you tons of time and money if you have a talented architect. Most plans are at least partly modular these days, and often you can even order prefabricated sections pegged to a specific house plan.
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.
If you find a house plan that you love, but want to make minor changes, most companies can have their designers do that for you, at an additional fee. It is also possible to have your plans reversed, for instance, if your breakfast nook faces west but the view from the north side of your lot is more attractive, you can reverse it. Many of the sites selling house plans will allow you to see a reversed view, of houses you might want to build.
Another item which is often missing or lacking in a set of house plans is comprehensive and accurate dimensions. We have always strived to provide more than the minimum amount of house dimensions so that it is easy for the owner and builder to layout a home on its building site. We will even calculate point to point dimensions (using trigonometry) for homes which have lots of odd angles to them (as opposed to a simple rectangle layout). Not all architects or designers will go this "extra mile," so it pays to check these things out beforehand.