The removal spells in here are quite nice, and theres a bunch, but my vote for unexpectedly powerful dark horse here is the instant-speed tutor (note the flash text there!): Waterlogged Teachings / Inundated Archive Bloodsoaked Insight / Sanguine Morass Boggart Trawler / Boggart Bog Bridgeworks Battle / Tanglespan Bridgeworks Disciple of Freyalise / Garden of Freyalise Drowner of Truth / Drowned Jungle Fell the Profane / Fell Mire Glasswing Grace / Age-Graced Chapel Hydroelectric Specimen / Hydroelectric Laboratory Legion Leadership / Legion Stronghold Pinnacle Monk / Mystic Peak Razorgrass Ambush / Razorgrass Field Revitalizing Repast / Old-Growth Grove Rush of Inspiration / Crackling Falls Sink into Stupor / Soporific Springs Strength of the Harvest / Haven of the Harvest Stump Stomp / Burnwillow Clearing Sundering Eruption / Volcanic Fissure Suppression Ray / Orderly Plaza Waterlogged Teachings / Inundated Archive Witch Enchanter / Witch-Blessed Meadow And you gotta catch 'em all for Commander

A further explanation for not banning the troublesome duo from the Lord of the Rings MTG set is that "Not many games are quickly decided by a runaway from either The One Ring or Orcish Bowmasters, allowing players to play longer interactive games with plenty of back-and-forth." As for the unbannings, Preordain, a card banned since 2011, is back in Modern, and Mind's Desire, which was swiftly banned in 2003, is back in Legacy
With that in mind, we're going to add a wrinkle to our plan
Wizardcycling (, Discard this card: Search your library for a Wizard card, reveal it, put it into your hand, then shuffle.) When this creature enters, return target Sliver to its owner's hand