DC Collector's Guide
The Dreamcast Collector's Guide is a document that spans 52 pages and it the culmination of over 3 years of work by its creator Mike Phelan. Currently at revision 1.5, the Guide is a mightily impressive tome of knowledge and documents every single Dreamcast game ever released. Every single game. In every territory. Let that sink in for a moment, and then be even more gobsmacked that it also includes information on the slight deferences between various European releases of certain titles and also rates games in terms of rarity, price and special edition status. As well as this, the guide features listings for white label and promo editions, serial numbers and even a playability guide for Japanese releases - which basically allows you to gauge how much fun you'll be able to glean from an NTSC-J bargain without being able to speak (or read) Japanese. It doesn't end there though, as Mike has thought to include all of the indie releases and even includes upcoming games such as SLaVE, Hypertension and Elysian Shadows.
This document really is jam packed with information regarding the various release types of certain games and has detailed guides to the Sega All-Stars and Dorikore collections. The best thing about Mike's guide is that it is compiled as a PDF and can be downloaded for free and printed out. You'll need to create a free account at the hosting site in order to download it, but if you're serious about collecting for the Dreamcast, this check list is something you definitely need to have a look at.