TFU.net is the best resource you are going to find for everything Transformers. That includes all generations and all accessories. There is no book on the planet that is as comprehensive as that site.
I like Transformersland.com (http://www.transformerland.com/ident...nsformers.html) since you can easily search both figures and accessories by both colour and series. They also have an archive that contains all the figures for each series etc...
www.cobraislandtoys.com will help with anything bw and lower, you can search by colour of the accessories too, hasn't been updated with the newer stuff though