Best cards:
Minotaur for damage and speed
Unstable Potion + any weak monster (bat is the best option because of its vampirism)
Fairy next to you for +1 hp per turn which is useful for spark mage and not drawing any cards damage
Summon Totem
-Fire Totem:snipe enemies that may cause problems (for example all the ratfolks that build things)
-Heal Totem:healing random allies
-Buff Totem:adding damage to random allies (well paired with fire totem)
Smite for sniping any enemies that may cause problems
Blacksmith and Innkeeper for adding cards that are pretty useful and prevent you from getting card damage for longer
Snake is good for its deathtouch although you will need to keep it out of enemy monsters range and protect it.
Cards to NOT get:
Spider because too slow and other weak monsters cost less mana
Hell Critter because even though it costs 0 it does no damage so it's only useful as a decoy and there are always better weak monsters for decoys
Beast simply because Minotaur is better
Goblin because the other weak monsters have effects like vampirism and swarm while it has nothing but base stats like Hell Critter which is another reason not to get Hell Critter
Bonus Fact: if the death touch snake gets to the other mage and attacks, the death touch doesn't work.