mtg cards shuffle graveyard into library Feldon's Cane [Time Spiral Timeshifted] Learn from the Past

Slickshot Show-Off has all the makings of an aggro red card

Much unlike the previously mentioned Krosan Cloudscraper which offsets its own power through a drawback, all of Worldspine Wurm's abilities are strictly beneficial

// Vigilance On turns where the effect of Summon: Yojimbo's second or third chapter ability is applying, your opponents can choose not to attack with a creature that must attack if able as long as there is no other player, planeswalker, or battle for that creature to attack that wouldn't require a cost

All three of them could be #1, though

Being able to take Bone Saws and turn them into mana sources is very appealing and most likely will be a big player in Standard

However, the problem with Jwari Shapeshifter in Commander is that while the cost is incredible (a mere one generic and one blue mana), the drawback iswell, significant