Many black-based decks can create a hefty amount of Treasure tokens, and just creating and sacrificing two Treasures deals 4 damage to everybody else
Enter any creator of X/1 creatures, from Sokenzan, Crucible of Defiance to Bitterblossom, and the -1 killing the creature as soon as you equip it turns Skullclamp into one of the best draw engines in the game
Its in the same family of cards as Reclusive Taxidermist, Raucous Audience, and Druid of the Cowl, as it only provides green mana
Cards like Inspiring Overseer, Brightmare, and Settle Beyond Reality make a showing once more
Treat them as side quests rather than core value
It's not quite as good as the Commander's two damage, but pumping out an endless quantity of Goblins more than makes up for it