So Broken shore and 7.2 Invasions reward 2 color variants of a new transmog set. (Xorothian/Moonshatter/Ere'drun/Vileweave etc.)
Other 2 colors are from Combatant pvp (faction dependant) , or Cathedral (incomplete set)
Missing like 1 piece for some armor types gets really annoying :P
Wonder if they are limited time available (dunno if invasions stop in 7.3 or not).