From Bulbapedia, the community-driven Pokémon encyclopedia.
Mercury is a Pokémon TCG deck archetype based around the EX Delta Species cards Gardevoir δ and Starmie δ. The deck made use of the Metal Navigation Poké-Power of Starmie δ to rapidly draw Metal Energy, which Gardevoir δ Energy Jump could then move around with its Energy Jump. While the deck did not enjoy widespread usage in the metagame, the deck did enjoy popularity internationally, particularly in metagames featuring high incidences of so-called rogue (non-archetype) decks.
Mercury was an active archetype across two formats (HL-on and FRLG-on), and significant changes were made to the archetype between these two formats. The decklists appearing below are not official, and being that this is merely a deck archetype, any player may wish to change any part of this deck when building their own version.
The deck's creator and its most notable proponent was Bulbagarden webmaster Archaic, who used the deck to win his local State and City tournaments in Australia.