Devilsaur Leathers , but those are probably heavily camped.
Black Lotus if you know the spawn rates/spots and timers inbetween respawns.
Farming Dungeons for example
Dire Maul aoe for mages, Bosses for hunters
Dire Maul hyenas + skinning , ( hunter,warlock, mages)
Maraudon bosses ( gotta have the scepter from quest) - Warlocks, Mages, Hunters ( best)
Don't know at what stage Kronos is right now, you could also check for how much the Crusader Enchant Recipe is selling for and farm that off the mages or whatever they were called in Wplaguelands towers.
Blackrock Depths - aoe if mage
rogue -> pickpocket in the arena
could go on and on, would be a lot easier if you stated your class