A spell card can be identified by having the white background and the word Spell on the back of the card.
You can find the list of all the game's Spells on the Spell List page.
There are 5 different spells with 4 varying levels in the Base Game, giving you 20 different variations of spells, and with only using 3 per game, that offers you several different spell possibilities! Each spell is represented by different colored dice, similiar to the rest of the cards in the game, and are based off of different points of a Quarrior's life; i.e. Victory, Death, etc.
Rise of the DemonsEdit
All we currently know about the new spells which will be released in this upcoming expansion is that they will encompass "Corruption Spells!" I guess we will see as November fast approaches.