nsfw card sleeves mtg "Unstable Unicorns" Complete Compatible Sleeve Bundle (8810 X 4) you may cast the copy without paying its mana cost. Gilfred – The Toy Maker

Or, how about PlaceholderSubType476, probably better known as Changelings in Standard

If you're wondering just how all of these ideas have been translated into actual cards, you'll be pleased to hear that the entire set has now finally been unveiled over at the MTG card gallery

Discounting activated abilities of of lands you control by 1 is pretty significant and makes cards like Nykthos, Shrine to Nyx (currently ruining lives in Pioneer in a mono-green deck, coincidentally) and Cabal Coffers that much easier to abuse

The best deck to take advantage of Trial of Knowledge is Brago, King Eternal, where you can keep drawing cards every turn by blinking it