Many of them, include the premium games, still use a card-buying mechanism. For example, the recent Age of Rivals has no microtransactions, but you still earn gold and buy packs. Same with Card City Nights and Lost Portal. I do reccomend all of these, especially Lost Portal if you're looking to scratch the MtG itch.
One game that comes to mind where you don't need to accumulate a collection is Summoner Wars, which is a fantastic game both in the table and on mobile (though I don't recall how well it functions in the current version of iOS). You do need to purchase more cards for the full experience, but you do so by buying armies, which are complete packs. You start the game with the Tundra Orcs and Phoenix Elves (for free, I believe) and can buy armies one at a time or all in a large bundle.