Elemental HERO decks have options for plenty of Fusion Monsters, as well as Link Monsters if you dip into the Xtra HERO lineup
How it works is that you co-link monsters from the one Extra Monster Zone to the other Extra Monster Zone, forming what looks like a necklace
Among the familiar legendaries are Pokemon Silver and Gold cover stars Lugia and Ho-Oh, Dialga and Palkia from Diamond and Pearl, and Groudon and Kyogre from Ruby and Sapphire, among others
Commander: Shelob, Child of Ungoliant
I think back to how much damage I was able to do with a lowly Birds of Paradise backed by Rafiq of the Many and Finest Hour and imagine the fun I can have with a trampling, double-striking, lifelinked Phelddagrif with two attack steps ("Heres a hippo token for your trouble.")
It does 20 DMG to your opponents Active Spot Pokmon every time you attach a Dark Energy to it