Zidane:

Ultima Weapon

Considered the most powerful weapon in the world.

Location: Use a Dead Pepper where the Shimmering Island used to be.


Garnet and Eiko:

Tiger Racket

The most powerful long-range racket.

Location: Use a Dead Pepper at the patio of Quan’s Dwelling.


Garnet:

Whale Whisker

Legendary weapon that holds powerful magic.

Location: Dig up a treasure chest at the Ocean chocograph location.

Eiko:

Angel Flute

Legendary flute that is said to enchant anyone who hears its tune.

Location: Find in Memoria.

Steiner:

Excalibur II

The ultimate sword, used by a legendary king. It was forged in another world.

Location: Reach the Terrace in Memoria within 12 game hours, then check the pillar to the right of the exit after defeating Lich.

Vivi:

Mace of Zeus

Legendary staff that once belonged a grand magician.

Location: Find in Memoria.

Freya:

Dragon's Hair

Legendary spear made from the dragon king's hair.

Location: Use Dead Pepper at the western crack on Forgotten Continent.

Quina:

Gastro Fork

Legendary fork known for its ability to crush anything.

Location: Catch 99 frogs in the Qu's Marsh, then challenge and defeat Quale.

Amarant:

Rune Claws

Legendary combat claws that possess tremendous powers.

Location: Find in Memoria.
I hope that helped.