Collecting Yixing isn't really my thing, so I only have a couple, but I figured I'd list them:
* Yixing Pottery: The World of Chinese Tea Culture by Chunfang Pan, 2004. This is a Long River Press translation. I think they produced a lot of these, as they don't have the markups you see on some other Yixing books. I think this might be a good 101 book for Yixing, as it gives a basic history, outlines different shapes you might see (helpful as online only one or two are really popular, sort of giving the impression that any other shapes can't be real), lists a few famous potters and up-and-coming (probably also famous now) potters, color photos of famous pots, etc.
* Selected Works of Contemporary Yixing Potters by the Hong Kong Museum of Art, 1994. This is a good example of what is one of the standard styles of Yixing lookbooks, the exhibition catalog. These are mostly produced by museums at the time of a show and are very affordable when they first come out, but apparently nobody buys them so the prices go up as time goes by.
They usually include intro articles by various Yixing personalities, so they can be good for finding out which authors to look for. This one has an intro by K.S. Lo, for example. A third stream that I don't have any of but that are a good source are paper auction catalogs from the big auction houses (Sotheby's, Christie's, Bonhams, etc.) as every so often a specialist shop will close or a collector will die and they will have a Yixing-dedicated auction. As the big auction houses make sure to verify what they are selling, the catalogs can be useful even if you don't buy anything.
Hopefully others will be able to add on here.
