If you are looking for "pieces" in the sense of campaign content or modules, here are the core classics:

: These cards are the primary mechanical "pieces" of the 2010 edition. Players draw random mutations at the start of encounters, and Omega Tech devices are used as temporary powerful gear. To help you find the right item,

: This official 20-piece metal miniature set was released in the early 1980s by Grenadier Models . It includes various mutant creatures, robots, and adventurers found in the game's early editions.