O-Naginata (2XM foil 50, SOK foil $5) I wish there was a sweet version of this to go after, but again, adding three power is where both legends are happiest and this time it is as cheap as can be, no need for ways to cheat the equip cost
(Equipment, Auras you control, and counters are modifications.) If the creature you control is an illegal target as Signature Slam tries to resolve but the creature you don't control is still a legal target, each modified creature you control (which may include the target creature you control if it's still on the battlefield) will still deal damage equal to its power to the creature you don't control
Pretty cheap
If you were willing to dedicate sideboard slots to the do-nothing artifact, you could have an improved matchup against graveyard-based decks
Traveling Chocobo Rarity: Mythic Rare TYPE: Creature SUBTYPE: Bird CMC: 3 Mana cost: USD: $18.41 EUR: 19.29 TIX: 0.25 EDHREC RANK: 2058 (3/2) You may look at the top card of your library any time
Damaged Damaged cards have extreme border wear, marking, folding or scratching, water damage, holes, etc