by MDJD
Well, it's hard for me to answer that question, as I'm the only one in my area with the game so far, and I've just built the decks and given my opponent their choice.One thing you can do is add the Core Spell Tome to your card collection to increase the number of general utility cards you have.
Honestly, Im not sure how big of an issue this is going to be. Many of the singletons either belong to a particular mage, or they are epic, or just don't go that well with certain mages.
Secondly, I don't think I've yet to put a spellbook together which has more than three of any one card, and even that is a rarity. It seems to me that if you are overly reliant on a particular card or strategy, you won't win all that often. In my short time with this game, it appears that a diversity of spells is pretty important. I don't think this game works like MtG with its hyper-focused decks.
Now, as more people get Mage Wars, this may change, but at the moment, I don't see card scarcity as a major issue.