Online "catalogs' of furniture places supply lots of pictures; Restoration Hardware, Williams-Sonoma, Ethan Allen, Ikea, Thomasville - there are many others. These should provide lots of visuals to help pick a style. Joe's picture above already show an amazing range.
Many of the online places also provide overall dimensions - that should give you sense of the 'standard' sizes. I have to say though that one great reason to build your own is to provide something that fits the space - you are not limited to 'standard' sizes. Good proportions in a piece certainly help the look, but you can up or downscale pieces to fit your usage.
I know I am not answering exactly what you asked, but I am providing the methods I use when I go about the type of project you are asking about.
Henry