1st edition base pokemon cards Goldin [LLLL] Thunderbolt (100) Discard all Energy cards to use this attack. 1999 Pokemon 1st Edition Base

This has spawned so many toolbox strategies in any format where you want to play low cost Artifacts

Bidoof (Peelable Ditto) #59Common $19.40 Bidoof (Peelable Ditto) #60Common $17.50 Ditto #51Common $78.66 Ditto #4Holo Rare $111.98 Ditto #35Uncommon $67.81 Ditto #12Common $55.36 Ditto #27Rare $22.33 Ditto #17Rare $22.66 Ditto #108Holo Rare $42.34 Ditto #XY40Promo $85.95 Camerupt #14Uncommon $0.13 Ivysaur #2Uncommon $0.20 Slowpoke #19Common $0.19 Charmeleon #9Uncommon $0.24 Wartortle #16Uncommon $0.23 Melmetal V #47Ultra Rare $0.70 Blastoise #17Holo Rare $1.51 Lapras #23Holo Rare $0.27 Charmander #8Common $0.21 Lunatone #34Uncommon $0.14

Xolatoyac is the alternate commander for the precon, though it's leaning more on the +1/+1 counter subtheme than anything related to Merfolk specifically

Thats an awesome feat for a little guy

Commander Morophon, the Boundless Changeling (This card is every creature type.) As Morophon enters, choose a creature type