Didn't see this mentioned anywhere yet, but for people that don't know you can desynth the old i90 Primal Jewelry dropped from Garuda/Titan/Ifrit Ex. They have the same sucess rate as old i90 coil gear, and GSM can desynth them to get a chance at Demi Materia of Inferno/Crags/Gales. This actually moves just alchemists from being the sole providers of Crag materia. Not that farming the old Exs would be better than farming Titan HM, but it opens up options. Unsure if you could get other forms of demi materia this way or not (such as Mastercraft, Battlecraft etc).

You can also desynth your old Twin weapons as well, but they are i95 and obviously are a little harder to desynth sucessfully. Unsure if Levi weapons are desynthable yet. Happy hunting!