Temporal Guard
An organization looking for events from the past that should never have happened, and trying to fix those, as well as trying to prevent some events from happening in the future.
A kind of fanatical organization, consisting of both devoted templars and wise wizards, who 'know the correct flow of time, and hate anything that seems not to match their vision of past and future'
It would be an interesting concept, since these guys might often do good things, or at least their goals might be good, but their methods might sometimes seem cruel and ruthless. It could be interesting to work for these guys, while in fact you don't agree with their methods, and thus you try to gain respect and power in the organization, aiming to change it's behavior once you get to the top. Sometimes you'd have to do things you don't agree with (like attacking an allied NPC, since 'he was meddling with Time too much', or you'd have to somehow avoid doing the quest, but make the guild believe you did (eg. by warning the NPC and helping him to disappear unnoticed, while faking his death). Of course this might seem like too much roleplaying for an MMOCCG game
Anyway, I can't really think of interesting quests and fable related to "The Clockmakers Guild"
Quests like "Gather 10 gears, 3 clock hands, 10 kg of sand and some glass? - we want to make a clock"
Seriously? xD
Archivists Guild would be much more interesting, trying to collect forbidden books from ancient ruins and stuff like that.