Flatline Flatline has a nice potential of being a fog for 3 mana, a huge combat blowout, or even a two-card sweeper in decks that have the potential to deal 1-2 damage to every creature
Shuffle your library, then put the revealed card back on top of it
I remember this power from back in the Base Set days
Spirit Water Revival, from Avatar: The Last Airbender , has a huge ceiling: you reshuffle your graveyard, draw a huge amount of cards (nine in total!), and on top of that you get the effect that gets Spirit Water Revival into this ranking: no maximum hand size
Some card effects affect your ability to play lands
Funnily enough, Sewers of Estark and Windseeker Centaur have still not received any reprints, and yet significantly fewer people seem to care about those two cards