Qeynos Guard ++FactionFollow

Unfortunately there are very few (none in most cases) mobs that give +city factions for killing them. If there were it would discourage people from doing that factions' writs. if you haven't done them already, look into the newb line of quests for your racial neighborhood (the ones that start with your racial representative on the dock in your hometown). It's an easy line of quests that ends up giving + faction with all the factions in your city at different points. At the very least this will get you some extra faction beyond just the writs, and if you mentor down you may even get some OK AA exp out of the deal. If you've done those already though...*shrug*.

I'm not sure about Qeynos Guard, but the Freeport Militia newb faction quests go well into the Commonlands and you can actually get a nice chunk from them.