I want to make this as a list or encyclopedia of all the custom mechanics on MTG Cardsmith who's creator has given permission for anyone to use - If you post a mechanic to this discussion, I will put it into the encyclopedia and credit you for it! Remember, these mechanics are here for ANYONE to use - if you need inspiration, look no further!
Archery X (This permanent enters the battlefield with X arrow counters on it.) By ChargingBadger.
Burn X (Whenever a source damages this creature, this creature deals X damage to that source's controller.)
Glow (Whenever you cast a spell, put a glow counter on this permanent. At the beginning of your upkeep, remove a glow counter from this permanent.) By ChargingBadger.
Versatility (Cost: Switch this creature's power and toughness until end of turn.) By ChargingBadger.