The Elemental Blades
There were 4 Elemental Blades created before the Great Loss. During this time the Blades were shattered into 4 pieces which were scattered throughout the Dream. These are the 4 Blades that were created.
SoulMaster - Serpent's Venom
Shards for Serpent's Venom were last known to be held by House Calenture.
DreamSeer - Dreamer's Blight
The only one to be reforged, Dreamer's Blight, was last held by Kard, the first Dreamer to hold the 7th Sphere position since the Great Loss. It is rumored that Luintari now has possession of Dreamer's Blight.
GateKeeper - The Protector
Dreamers of Light is believed to hold shards of The Protector.
FateSender - The Destroyer
Order of The Sable Moon may have shards for The Destroyer.
Obviously not all the Shards have yet been found, or some of the pieces may be held in secret. Each of the blades were broken into The Blade, The Pommel, The Hilt and The Scabbard.