Confirming what the 20 additional cards are, at least card type wise.

Firstly, the Sneak Preview has the chance of getting your hands on this Supreme King Z-ARC mat:

As well, we can confirm the Type identities of the following 20 Imports and TCG World Premieres

MACR-EN081 = Xyz Monster

MACR-EN082 = Effect Monster

MACR-EN083 = Effect Monster

MACR-EN084 = Effect Monster

MACR-EN085 = Trap Card

MACR-EN086 = Effect Monster

MACR-EN087 = Effect Monster

MACR-EN088 = Spell Card

MACR-EN089 = Trap Card

MACR-EN090 = Spell Card

MACR-EN091 = Effect Monster

MACR-EN092 = Normal Pendulum Monster

MACR-EN093 = Xyz Monster

MACR-EN094 = Effect Monster

MACR-EN095 = Normal Pendulum Monster

MACR-EN096 = Normal Pendulum Monster

MACR-EN097 = Ritual Monster

MACR-EN098 = Spell Card

MACR-EN099 = Trap Card

Source