I believe for the most part, adding these is relatively safe
"How Magic: the Gathering became a pop-culture hit and where it goes next"
Good enough that it's still worth a few bucks even after repeated reprints
Tutors: Transmute Artifact, Gamble, Mystical Tutor, Personal Tutor Ramp: Mana Crypt, Solemn Simulacrum, Thran Dynamo, Gilded Lotus, Mana Vault, Grim Monolith, Basalt Monolith, Voltaic Key, Coalition Relic Disruption: Force of Will, Mana Drain, Counterflux, Vandalblast, Blasphemous Act, Pongify, Rapid Hybridization, Cyclonic Rift Draw: Rhystic Study, Recurring Insight, Consecrated Sphinx Utility: Lightning Greaves, Ral Zarek, Time Stretch, Dack Fayden, Sensei's Divining Top Lands: Academy Ruins, Strip Mine, [Reliquary Tower]], Command Tower, Sulfur Falls, Steam Vents, Shivan Reef, Desolate Lighthouse, Cascade Bluffs, Scalding Tarn, Volcanic Island, Minamo, School at Water's Edge, Ancient Tomb, Myriad Landscape If you're mad enough to fully bling out a Coin Flip deck, then here's a list for you to ponder: Next One's A Secret

Here the cards are gorgeous, two-dementional drawings that look like highly stylized versions of the characters, items and locations depicted in the films their ideas spawn from