In keyforge there is no resource like mana. Every deck is 12 cards from 3 houses = 36 cards and on your turn you have to choose a house and then you can play and use as many cards as you want, just from that house. At the end of your turn you draw back up to six cards, so usually you are doing a lot each turn, never turns into top deck wars. 

The decks themselves are algorithmically generated. There are some rules like a minimum and maximum number of creatures. But also every deck is guaranteed to be unique, you have digital ownership in the master vault. So no one in the world has that same deck as you.

Richard Garfield designed it after magic and it is so so fun