How do the colors work in Lorwyn / Shadowmoor?
I don't know what they'll do in the new incarnation, but the old Lorwyn was focused on creature types – what was then called "tribal" and now called "typal" I believe? So you had goblins in black and red, elves in green and black, faeries in blue and black, merfolk in blue and white, giants in red and white, kithkin in white and green, and treefolk in green, white, and black. You also had two special cases. Changelings showed up in all colors and have all creature types, and mechanically acted as a way to make it easier to satisfy creature type requirements. Elementals came in two types: "flamekin" who were humanoid and red-aligned, and were basically "burning people", and "greater elementals" who were weirder and more monstrous/animalistic and usually had Evoke (cast for a lower cost but sacrifice it right away, usually combined with an ETB effect).
Then you had the follow-up small set, which shifted the focus to class-style creature types (Warrior, Shaman, etc.). After that you had Shadowmoor, a big set set on a Lorwyn-turned-dark, somewhere in the space between fairy-tale and horror. You had mostly the same creature types, but most had changed color alignments. Shadowmoor (and its corresponding small set Eventide) was more color-based, and heavily featured hybrid mana (costs that could be paid with either of two colors), but the mechanics were more along the lines of "color matters" rather than having keywords tied to particular colors.
All in all, the sets didn't have a particularly strong mechanical identity with keywords tied to particular factions or colors. Instead, their main focus was "creature type/color matters". The main thing the sets are remembered for today are the fairy-tale vibes.