
Unfortunately, outside of draft and Scars of Mirrodin block Limited formats, Slag Fiend really never found a permanent home. There were some decks in the New Phyrexia era that used him as part of a bigger strategy built around the sorcery Scrapyard Salvo. Today, he's just a bulk rare that doesn't really fit into any larger strategies. But because of his raw power, you never know if he'll pop up again some day!