Copied from this thread and modified.
All of the following promos are legal for play at the Kotei events. Any others that are currently in circulation will not become legal until the legality date of Drums of War.
Actions
Dire Omen
Emerald
Imperial
Kill the Messenger
Mysteries of Kawaru
Provocation
Events
A Time for Vengeance
Bushido
Death of the Heartless
Harvest Festival
The Price of Power
Holdings
House of the Fallen Blossom
Secluded Waystation
Shrine to Osano-Wo
Venerable Master
Vengeful Populace
Items
Mark of Oblivion
Rosoku's Staff
Ryokan's Sword (Experienced)
Sword of the Righteous Emperor
Utaku Stallion
Yamainu's Dagger
Personalities
Junji
Kihei (Experienced)
Miya Nishio
Seppun Kiharu
Shadow Dragon (Experienced); most recent printing in Lotus Edition
Yamainu
Regions
Tormented Plains
Tsuno Swamps