Munchkin Hidden Treasures consists of 78 individual cards for use in a variety of Munchkin games, with all of these cards previously being available solely in annual booster packs sold via Warehouse 23, the Steve Jackson Games online store. Sample cards include:

- Can of Worms from Munchkin

- Great Caesar's Ghost from Munchkin Bites

- Iron Chef R'Lyeh from Munchkin Cthulhu

- Mr. Spork from Star Munchkin

A few odd-sized cards from previous Warehouse 23 boosters are not included in Munchkin Hidden Treasures.