Mechanics are the rules that will trigger based on events that happen within the game.
Battlecry
The stated effect activates when the card is played.
Charge
This minion may attack the turn it is played.
Choose One
When some condition is met, the controlling player may choose which of a number of effects activates.
Combo
The stated effect activates if this is not the first card played this turn.
Deathrattle
The stated effect activates when the card is removed from play.
Divine Shield
The next time this minion would take damage, ignore it. The shield is then removed.
Enrage
The stated effect activates when the minion is injured.
Freeze
Frozen minions may not attack during their next turn.
Overload
Overload reduces the amount of mana you have available during your next turn by the number stated.
Secret
Card is cast face-down for no effect, effect triggers once a condition is met. Opposing player can see that there is a "Secret" card, but does not know what triggers it or what effect it will have.
Silence
Removes all buffs and all effects (even those written on the card) from the target while the target remains in play.
Stealth
Minions with Stealth may not be the target of attacks, spells or abilities until they attack. Once they do, Stealth is removed.
Spell Power
Boosts the damage of spells by the listed amount
Summon
Creates a creature under your control with the specified attributes.
Taunt
If an enemy is attacking, they must choose targets with Taunt until none remain (they may choose which to target if there are multiple).
Transform
Changes a minion into something else irreversibly.
Windfury
Minions with Windfury may attack twice in a turn.