From Bulbapedia, the community-driven Pokémon encyclopedia.
Hideki Ishikawa is one of the newer TCG illustrators, starting with Magmar from the Generations expansion. He was also involved in character illustrations of Pokémon Duel. Outside of Pokémon, Ishikawa was the character designer and illustrator for some of the Mega Man games.
For the complete list of cards that he illustrated, go here.