Primals (if you have a good group) can be a very quick and easy farm (easy: Garuda, Shiva, Titan / be mindful of mechanics: Ramuh, Ifrit / go die in a fire: Leviathan). You can also get some decent glam weapons, crafting materials (which make nice bardings for your chocobo, as well as weapons!) and if you level desynth, is a great way to get battlecraft demimateria III, which sell decently. King Mog doesn't have a mount but his crafting items go for a lot, and make some really cute weapons. Plus, once you get 60, they can be a good way to fill your Wonderous Tails, which can sometimes give minions.