From Looney Pyramid Games Wiki

A monochrome stash is a set of 15 pyramids in a single color.

Above is a green monochrome stash.

Pyramids have been sold in monochrome Icehouse Stashes, Rainbow Treehouse sets, and Xeno Stashes. Currently (as of 2019), pyramids are only available as part of the Pyramid Arcade game set.

Monochrome Chess, a game invented by Andy Looney, is the inspiration for his later invention, Martian Chess.