I would strongly reccomend taking a look at
Duelyst. It has similar mechanics to Hearthstone for the most part, just with the addition of a gridded board to play on. It makes a huge difference to how the game plays out, and brings something fresh to what is otherwise a rather repetative formula. As a bonus, there are very few high varience cards that exist in Duelyst, and the ones that do exist aren't played too frequently outside of gimicky decks. Finally, it's also got a very full Lore section you might like to take a look at, complete with lore for some, not all, cards. Though the Lore is still very much a work in progress.
There is also
Faeria, which plays closer to MTG with the addition of a Hex based board. You get to slowly fill the otherwise empty game board with Lands as you play, which is both a nice touch and opens up some interesting options that wouldn't otherwise exist.
For something completely different, you can try
Runescape Chronicles. It's set in the Runecraft universe, so has some Lore to it, though you don't need to be invested into it to enjoy the game. Interestingly enough, it pits your Avatar against
your own cards, before forcing you into a duel with your opponent at the end, assuming you both survive. It makes deciding which cards to play, and in which order, far more important.
Finally, for something very familiar you can try
Spellweaver. It plays very, very similar to MTG, just with a few minor changes to the formula. Being able to replace a card in your hand for a Shrine, their equivelent of Lands, means you're less likely to get screwed for resources. Personally, I think it would be a more enjoyable game if they took a few more risks with the formula, but it's solid enough for what it does.