You have a chance to receive any 1 of the following:

64x Zombie Spawners — 14.1% chance
64x Spider Spawners — 14.1% chance
64x Skeleton Spawners — 14.1% chance
64x Creeper Spawners — 14.1% chance
64x Blaze Spawners — 14.1% chance
64x Phantom Spawners — 14.1% chance
64x Iron Golem Spawners — 14.1% chance
64x Evoker Spawners — 1.4% chance (rare!)

Spawners are stackable and generate drops you can sell for money.