Masters 25 Booster Pack. 15 cards per pack.
This set contains many great cards such as:
Jace, the Mind Sculptor
Imperial Recruiter
Rishadan Port
Chalice of the Void
Ensnaring Bridge
Vendilion Clique
Animar, Soul of Elements
Blood Moon
Plus many more great cards! No card is guaranteed in a booster or box but these are some of the great cards you could get.