Since we have a topic for future card ideas (which imo should be an entire subforum), I would also find future mechanics (such as Bloodthirst, Enrage or Vigilance) an interesting topic to talk about.
So here go ideas about possible new mechanics:
Selfdestruct 2 (Pelagoth)
Character explodes on death, dealing X damage to other characters in the same zone, where X is the number of Selfdestruct.
Overload 4 (taken from HS) (Pelagoth)
Character overloads, reducing your availible resources by X at the start of the next turn, where X is the amount of overload.
The first time the character with challenge is moved to the battlefield, you may target a deployed enemy character. Targeted enemy character moves to the front of the same zone and becomes untouchable at the start of the turn (deployed character with challenge also moves to the front of the zone).
Life Bond (Pelagoth)
When deployed, you may choose to target another friendly character . Each time the character with Life Bond takes damage or is healed, the damage or heal is split between targeted friendly character and the character with Life Bond.
Leap 2 (Pelagoth)
Deployed character ignores X enemy characters while in the Assault Zone, where X is the amount of Leap.
Aggression X (Brueson)
While this character is in the assault zone, it gets +X/0 where X is the aggression number.
Base power and health of this character is always equal to the highest values plus 1, based on all deployed characters that share the creature type of this character.
Meaning, if there are 5 Demons deployed with power and health like so; 1/6, 2/5, 3/4, 12/1, 7/7. Then the paragon's base power and health would be 13/8. This changes as demons come and go and if all other demons are out of play, the paragon would be a 1/1.
Instead of paying this card's resource cost you may instead pay 3 and put this card into play as a 7/7 character.
A masked card returns to it's original form. Can be triggered by various effects or be an activated ability.
This card cannot be seen by your opponents until it attacks, blocks, takes damage, dies, activates an ability, or is affected by an ability
Dodge X (RuggedKnot)
Deployed character ignores X enemy characters while in the Defense Zone, where X is the amount of Dodge.
Character is removed from the game at the end of turn. The Character is then returned to play at the beginning of next turn.
When a Character with Mimic enters combat with another Character they gain any Abilities the character has until end of turn (IE: Flying, Flamestrike, Unstoppable)
Preemptive: Can not attack or block until end of turn or permanent. (Best as Ability card)
Characters always deal their damage first, should this kill the character they entered combat with they take no damage.
Improvement tip: "Make it like Shield 1. Except you just get Swiftness 1. That is how many times it can trigger per round. Problem solved for the majority of OP setups."
The first time this character would die, it survives on 1 hp instead.
If this character is at full hp and it were to die, instead its remaining health becomes 1.
This character deals combat damage after its opponent during combat
If this character takes damage, it dies
This character can only block flying characters
Venomous X (Hiding)
Characters dealt damage by this source gain an additional X poison
Characters dealt damage by this source die at the end of the turn
Faceless X (Hiding)
you may have up to X copies of this card in your deck
When you draw this card it is revealed to your opponent.
Guard X (NatoPotato)
This character takes X less damage from all sources.
(just the effect used by armored landcrawler, gao han champion and great wall of jinhai but given a name)
Weakness X (NatoPotato)
This character takes X more damage from all sources.
(basically the opposite of guard, useful for giving to enemy cards, or to your own for certain combos, and yes if a character with 0 attack enters combat with a card with weakness it will deal X damage)
Regeneration X (NatoPotato)
At the end of the turn this character is healed for X damage.
(just makes characters a little more resilient, though not nearly as good as guard, as guard reduces the damage before combat while this does it after, also this only happens once per turn)
Fury X (NatoPotato)
If this character takes damage it gets +X/+0 until the end of the turn.
(pseudo-consume which doesn't require enemy character death but only effects power and is undone at the end of the turn)
Every time an adjectant character takes damage, half of that damage is redirected to this character.
Disturbing presence X (ToxicShadow)
Characters that enter combat with this character have -X/-0 attack until the end of turn.
Berserker X (ToxicShadow)
Once this characters health is equal or lower than half of his max health, he becomes locked to the assault zone and gains +X/+0
Astral Body (ToxicShadow)
Takes half combat damage, but double damage from abilities.
Impact X (ToxicShadow)
The first time this character enters combat, they gain +X/+0.
A creature with Burrow gains Untouchable and also can not be blocked by creatures with flying. (IE: Pay 2: Gains Burrow until end of turn. or Gains Burrow while in the Assault Zone)
If this character attacks and kills a defending character, it does damage equal to its power minus the defending characters health to the opponents fortress.
Manifestation - An ability mechanic (Choose One) (ToxicShadow)
You may choose to pay the manifestation costs instead of the normal cost of this ability. Instead of gaining the ability effect, you get a character/artifact/location.
A Frozen character cannot attack, be moved or use abilities, if the character would take damage or be affected by an ability the character becomes unfrozen and the ability or damage is avoided.
Opportunism 3 (ToxicShadow)
When an adjacent ally character deals combat damage to an enemy character, this character deals X damage damage to the same enemy character, where X is the number of Opportunism.
If this character takes damage when in combat with another character and that character survives, it enters combat with that character again.
Evade X (Hiding)
This character takes no combat damage and deals no combat damage during the first X combats each turn
Last Word X (Hiding)
After each combat, this character deals X combat damage to its opponent.
This character can not be removed from the game.
Resurrect X (Inspired by Aleta) (NatoPotato)
If this Character is in the Graveyard for X consecutive turns, it is raised to the Support Zone at the end of the turn.
Strategist (Inspired by Kung-Ji) (NatoPotato)
If this character blocks an attacker, it moves to the back of the Defense Zone.
If this character attacks and the opponent has multiple defenders, this character attacks the defender with the least power.
Thoughts, ideas and feedback are welcome.
Hope to see more creative mechanic ideas.
P.S. Please remind me if I forgot to compile any of your ideas in this list. Will update whenever I have time.