As many people were speculating, the world premiere card included in LC3 is The Seal of Orichalcos. We don't have an official text yet, but it's effect will include
1. Gives all your monsters +500 ATK
2. Highly resistant to removal from the field
3. Allows your stronger monsters to protect your weaker ones.
The first 2 effects are on par with the anime version, but the third effect is the most interesting. In the anime, it allowed you to play Monsters in the Spell/Trap zone. Stealing your opponent's soul is optional.
What else is included?
3 Ultra Rare Tokens: 2 Kuriboh and the Emissary of Darkness.
1 Ultra Rare Dark Necrofear
1 Ultra Rare Guardian Eatos
1 Ultra Rare Five Headed Dragon
1 Game Board: This hard-surface game board features Yugi on one side and The Seal of Orichalcos on the other, and folds up to fit in your backpack or binder.
Confirmed Mega Pack Cards
Seven Tools of the Bandit
Mystical Space Typhoon
Book of Moon
Black Horn of Heaven
Fling Kamikari #1
Dark Magician Girl
Almost every Gravekeeper card
Reinforcement of the Army
Bottomless Trap Hole
Dragged Down into the Grave