3. Fossil (FO) – October 1999

Closing out the original Kanto Pokédex, the 62-card Fossil expansion leaned heavily into prehistoric Pokémon and the legendary bird trio: Articuno, Zapdos, and Moltres. Fossil is a relatively small set, but it packs a significant punch in terms of iconic artwork. The holographic Dragonite and Lapras remain fan favourites, while the mysterious Ditto introduced a completely new mechanic of copying defending Pokémon's attacks.

Fossil also holds a special place in the hearts of early collectors due to the Aerodactyl Prerelease promo, which was distributed at the very first official Pokémon TCG League events. Fossil booster boxes, featuring the menacing artwork of Aerodactyl, remain incredibly highly sought after by sealed-product investors in the UK.