Ravnica Allegiance rounded out its support for the remaining five guilds with a lot of exciting cards for both Limited and Constructed play. To give a bit of an idea of what to expect, here are my rankings of the guild mechanics for Booster Draft and Standard.
Guild Mechanic Rankings for Booster Draft1. Adapt (Simic)Rule 701.42a - "Adapt N" means "If this permanent has no +1/+1 counters on it, put N +1/+1 counters on it."Two of the most common ways to lose in Limited are by being unable to do anything in the early game and by flooding out in the late game. Adapt does an admirable job of trying to solve both these problems, allowing you to deploy creatures early on and then providing a mana sink as you level them up into more formidable late game threats.
2. Afterlife (Orzhov)Rule 702.134a - Afterlife is a triggered ability. "Afterlife N" means "When this permanent is put into a graveyard from the battlefield, create N 1/1 white and black Spirit creature tokens with flying."
Limited matches usually involve some form of attrition as players battle for board superiority. Afterlife provides residual board presence in the form of Thopter tokens, ensuring that you come out ahead in creature combat and reducing the impact of opposing removal spells.
3. Riot (Gruul)702.135a - Riot is a static ability. "Riot" means "You may have this permanent enter the battlefield with an additional +1/+1 counter on it. If you don't, it gains haste."
As long as both players are able to enact their game plan and deploy creatures to the battlefield, haste doesn't affect the board state as much as other keyword abilities like first strike. It does let you take some of the initiative in the game and threaten to throw off combat math but, for the most part, you will generally just want the bigger creature. That said, there are a number of synergies with +1/+1 counters to provide some additional benefit.
4. Addendum (Azorius)
Addendum is an ability word rather than a keyword mechanic, which means that it isn't written directly into the rules of the game. Rather, the full functionality is explained on each card with the ability. What it does is provide a bonus to instant spells if you cast them during your main phase.
Addendum provides versatility as you can choose to have a more powerful effect if you're willing to show your hand by playing the card on your turn. Unfortunately, both options are kind of lacklustre as you don't want to play too many low impact spells or give your opponent extra information. Obviously, some cards will be good enough despite this tension, but the mechanic itself leaves something to be desired.
5. Spectacle (Rakdos)Rule 702.136a - Spectacle is a static ability that functions on the stack. "Spectacle [cost]" means "You may pay [cost] rather than pay this spell's mana cost if an opponent lost life this turn."
Most spectacle cards offer an attractive discount if you're able to meet the condition, and a much less attractive backup plan of paying the base mana cost. While it's nice to have the backup option, the fail case will often leave you saddled with a bunch of overcosted filler. To avoid this, you need to place a high priority on enablers which you might otherwise not want to include in your deck. It also forces you to occasionally make overly aggressive attacks that will sometimes play into your opponent's game plan.
Guild Mechanic Rankings for Standard1. Spectacle (Rakdos)
The problem of not getting enough enablers doesn't really carry over to Constructed where you can build the perfect mix directly into your deck. Standard decks are also much more streamlined for the role they want to play. Hyperaggressive decks, for example can usually count on being able to do early damage and apply pressure while slower midrange and control decks franctically try to stabilize. The discounted alternate costs are a welcome asset when you're able to consistently meet the condition.
2. Riot (Gruul)
Riot allows creature decks to customize their game plan for whatever matchup they're playing. Haste is a great way to punish control decks that tap out for a planeswalker or a sweeper spell like Kaya's Wrath, while also increasing the clock against non-interactive combo and ramp decks that take time to set up. In other aggressive creature matchups, larger creatures that are able to block effectively become the order of the day.
3. Afterlife (Orzhov)
Afterlife is a good ability in Standard, gumming up the board against small creature decks and presenting resilient threats against control decks that basically have to kill everything in order to stabilize. Where it falls short, however, is against decks that would rather ignore your creatures while they enact their own more powerful game plan.
4. Addendum (Azorius)
Giving extra information and tapping out on your turn is probably even more costly in Constructed than Limited, as opponents will look for openings to resolve key game-changing spells. This is especially true in Azorius decks which likely rely on permission spells like Absorb to manage opposing threats.
5. Adapt (Simic)
With Standard decks packing as much removal as they want access to, the last thing you want to do is sink a bunch of extra mana into a creature that can be taken out by a single, much cheaper spell. Creature decks need a very good reason to expose themselves to that kind of tempo loss.