Been awhile, but I don't remember Ultima Weapon in the game. I remember Durandal, if that counts...
Then again, I never got around to fighting the bonus boss as I wanted to give myself something to look forward to in the localized release. Zoel probably got more of the weapons in the game, so he'd probably have a better idea than I would.
PSN: Neophoton | NA 3DS: 2277-6964-8962 | JP 3DS: 2509-0978-4639 Currently playing: Fire Emblem: Awakening, Tomb Raider
Nothing like Ragnarok or Ultima Weapon, but stuff from older Final Fantasy games will appear. Like the Blood Sword, Muramasa, Masamune. Stuff from ancient japanese times, like the Genji series and stuff. Best thing to compare with is Final Fantasy Tactics, alot of the inventory in Bravely Default is very similar to the inventory you would see in FFT or some of the Ivalice games.
And I think the strongest weapon I have in my inventory is the Golden weapons, I don't even know what's the condition for unlocking them, but its a free DLC that is unlocked through acheivements.
AKA as Zoelius / PSN: Celis777 [ working on P4G Faq] P4A Main = Aegis / BB Main = Carl