The very first Monopoly tokens weren't even tokens, they were buttons, or coins, or whatever was available. When Charles Darrow produced his first games in 1934 there were no tokens included. Players were responsible for providing whatever they had available for markers. Parker Brothers, after acquiring the rights in 1935, provided the first metal tokens as we know them today. These were also included in the Patent Description, and originally included the Thimble, Cannon, Iron, Top Hat, Shoe and Battleship.
The early metal die cast tokens were made by the Dowst Manufacturing Company with a Zinc alloy called Zamak, also referred to as Pot Metal or White Metal. These were made from 1935 to 1938, and had a tendency to oxidize very quickly, why many of the original tokens have a poor appearance. This was a result of impurities in the manufacturing process. By the late 1930s these impurities were eliminated and used a metal token made of lead and tin, similar to those used today. The tokens were the same charms as Cracker Jack used and were made by the same company, Dowst, out of Chicago. The Dowst Company invented die casting and also made the first die cast cars ... Tootsietoys!
Foreign wartime versions of Monopoly also used Cardboard Tokens fitted with slotted wooden bases.
Today the Standard Edition sets include 8 tokens: The Dog, Battleship, Car, Top Hat, Thimble, Shoe, Wheelbarrow, and the Cat.
In the 1990's Hasbro began producing licensing variations of Monopoly to other companies, including USAopoly and Late-For-The-Sky Productions, to allow games to be customized for specific regions, schools, events, companies, and movies. Most of these variations were offered with unique tokens relative to the theme of the game. Hasbro also customized their own versions of the game. This, in effect, created an immediate collectors market as these games were not only sought as games, but became a "Cross-Collectible". Star Wars collectors loved the highly detailed Pewter Tokens, Firefighters found a new theme game for the station, and kids loved to play with the Disney themed characters. many of the early customized version were produced in extremely limited quantities, and have become quite sought after - and valuable - today.