Faction Mods
Diplomancer
Automagically watches factions based on your location.
WoWInterface, Curse
FactionFriend
Helps you keep tabs on whose respect you're earning, but also how much more you could earn by turning in certain items you're carrying.
WoWInterface
Factionizer
Displays how many reputation points are missing to the next reputation level in your reputation window. In addition, it extends the reputation detail window by showing how many points you need for your next reputation level and how you can best gain this reputation. It also shows how much reputation you can gain by handing in completed repeatable/daily quests and gathering quests.
WoWInterface