The first Pokémon Gym themed expansion of the Original Series, Gym Heroes, came with four Theme Decks when it was released to the public on August 14, 2000. Based on the first four Gym Leaders of the Kanto region, the four Theme Decks were named Brock, Misty, Lt. Surge and Erika, and each featured the signature type of their namesake: Fighting-type, Water-type, Lightning-type, and Grass-type respectively. These four Theme Decks each came with a rulebook, damage counters, an exclusive Starmie coin, and card list for the expansion.

https://bulbapedia.bulbagarden.net/wiki/Original_TCG_Series_merchandise#Gym_Heroes_Theme_Decks