I just started playing the game a few days back. I found the game and cards a bit confusing at the beginning but after playing the game for some time and reading about various cards I came to the conclusion about what types of cards one should focus on buying as a beginner.
Tanks : Mostly every game contains tanks and they are defense. So tanks should have high health and good melee attack power. I found the following tanks useful
Goblin Mech(Neutral splinter) (best for beginner)
Nectar Queen(Earth splinter)
Living Lava (Fire splinter)
Unicorn Mustang( Earth splinter)
Creeping ooze : I found this card very useful and it has only 1 mana cost. The card reduces 1 mobility point of all the enemy card's in the beginning of the battle which greatly helps. This card is great against pyre summoner which most beginners tend to use.
Furious Chicken : This card has 0 mana cost and 1 health. This can be used to fill the empty card spot during battle and waste the 1 enemy attack which can be crucial.
These are the cards I found useful in my battles and feel free to suggest.
