Clan — for Kaldheim. A modified version of Leader, adapted for use as a tribal mechanic. When you played a clan card, you chose a creature type, and the card affected that creature type. Then when you played a second clan card, you could rechoose your creature type, but both effects would affect the one chosen tribe.
Cooperation (Whenever this creature deals combat damage to a player, put a +1/+1 counter on another target creature.) for Throne of Eldraine. A variant of the Slith mechanic.
Debt — for Orzhov in Ravnica Allegiance. Spells give debt counters to opponents. At the beginning of their end step, they can get rid of any number of debt counters by paying per debt counter. Then, as long as they have any debt counters remaining, they lose 1 life (not per debt counter just 1 life total regardless of how many debt counters they have).
Discipline N (Whenever this card becomes blocked, put N +1/+1 counters on this card.) for Throne of Eldraine.
Jewel — For Guilds of Ravnica. It went on any instant or sorcery. After the card resolved, it got exiled. Then, whenever you cast another instant or sorcery, you could play the first card for free from exile. The idea behind it was that we built smaller effects that comboed together to do cool things.
Joust (When this creature is blocked, it gets +0/+N until end of turn. If not blocked, it gets +N/+0 instead.) for Throne of Eldraine.
Leader — for "Salad", an unmade set intended to follow on from Dominaria. Whenever you played a leader card, you chose a leader from among your creatures, and that card granted an ability to your leader. If you played a second leader card, you had the option of changing who your leader was, but both cards would grant abilities to a single leader.
Mechanic I — For Kaladesh. The only unexplained mechanic of the five that the Kaladesh design team ended up making and liking. It got discarded for excess of mechanics.
Reckless — For Gruul in Gatecrash. An ability that sacrificed the creature at the end of the turn when triggered.
Resistance (This creature isn't a legal target of a spell or ability an opponent controls unless they pay as that spell or ability resolves) for Ikoria: Lair of Behemoths
Reverse Engineer — For Kaladesh but pushed for Aether Revolt. It allowed you to copy an artifact and then that copy got sacrificed at end of turn, in the same way Heat Shimmer from Lorwyn does for creatures.
Roar — By Mark Gottlieb, for the Dinosaurs of Ixalan. "You may pay [cost] and exile this card from your hand. If you do, you can still cast it this game. When CARDNAME roars .... [effect]". Led to Adventure.
Showoff — By Mark Rosewater, for Lorwyn. It allowed you to choose to reveal a card. If the card was revealed (from your hand or your library), then it could be played for its showoff cost, which was often cheaper than its normal mana cost.
Skirmish — for War of the Spark. "Create a Skirmish if one hasn't been created yet." The Skirmish token has a tiny "game board" on it showing a field of combat. When you perform one of the stated conditions, you advance on the field toward the opponent's side. If you have advanced enough, you win the skirmish. There is a payout for winning, a generated effect.
Stopwatch — mechanic forces you to do certain actions in a set amount of time. Considered for Unstable.
Stygian — for Theros Beyond Death. When you play a card with the stygian mechanic, it brings onto the battlefield a special card from outside the game that represents the river of the dead. Creatures on the living side could only block creatures also on the living side while creatures on the dead side could only block creatures on the dead side.
Titan — for Zendikar Rising. A kicker variant where the mana cost was always generic and always seven or more mana. It tended to mega-juice the spell. The flavor was that you were tapping into some residual Eldrazi energy that was seeped deep in the land. 
Unique — By Mark Rosewater, such mechanic is intended to narrow the Legendary rule effect which would be applied only to legendary permanents having the Unique ability.
Unnamed — By Mark Rosewater, for Tempest. It allowed you to choose to start with the card in your opening hand. If you chose to do so, you had to begin with one card fewer.
Unnamed — By Mark Rosewater, for Time Spiral. It allowed you to put cards into your deck that you might not normally be able to play. The idea was the card say that if it was in your deck, then you were allowed to have up to four copies of a card from the past in your deck —even if that card wasn't normally legal in Standard. Understanding that those cards might not be broken cards, Mark Rosewater found six subsets of past cards, one for each color and one artifact, that could work —blue's member of this cycle was a creature that had the creature type Wizard, which would allow any previously published Wizard to be legal in the deck.
Unnamed — For Amonkhet. It made use of -1/-1 counters to represent the ruthlessness of Bolas.
Valiance (Whenever this creature deals combat damage to a player, put a +1/+1 counter on it.) for Throne of Eldraine. This is the Slith mechanic.
Ward (Once each turn, you may draw a card while this creature's the target of an opponent's spell or ability) for Ikoria: Lair of Behemoths
Quest (other mechanic than the released Quest enchantment) — For Zendikar and Throne of Eldraine. Enchantments that gave you three tasks. You marked them with counters as you finished each one. Once all of them were completed, you could sacrifice the card for a big effect. Some got you the legendary artifacts for each court.
Über-classes — By Mark Rosewater, for Morningtide. Cards that affected "fighters" affected Soldiers and Warriors (and possibly Knights). "Mages" were Shaman and Wizards (and possibly Druids). "Scoundrel" meant Assassins and Rogues. Similar to the later batching.
This page was last edited on 13 January 2021, at 00:36.
Content is available under CC BY-NC-SA 2.5 unless otherwise noted. Game content and materials are trademarks and copyrights of their respective publisher and its licensors. All rights reserved.
This site is a part of Fandom, Inc. and is not affiliated with the game publisher.