The Base Set or Base Set 1 as it's sometimes known was the very Pokemon TCG expansion to be released and was widely responsible for the Pokemon Card mania of the late 90's. The set contained 102 cards and was initially released in Japan on October 20th, 1996 - it wasn't until years later that the English release hit western shelves on January 9th, 1999.
There were a number of theme decks released alongside the main card collection including the 2-Player Starter deck as well as the Blackout, Brushfire, Overgrowth and Zap! decks.
Numerous "final form" evolution's of popular Pokemon were left out of the release including in spite of their un-evolved forms being present in the set for example no Butterfree, Clefable, Dragonite or even Gengar were present and these and others were later released in card form within the Jungle and Fossil set expansions.
Titan Cards offer a wide variety of these retro Pokemon Cards from the original Base Set of the Pokemon TCG including common, uncommon, rare and rare holo cards.