Blue/Green Merfolk

Kumena, Tyrant of Orazca — If you read the stories on the Wizards web site, then you know that the Kumena character is actually a minor villain. If you don't read the stories, then maybe you could infer that by the word "Tyrant" and the way his manic smile resembles Jared Loughner's mug shot. His abilities are clearly suited to a deck that is heavy on the merfolk tribal, and he looks to be better at that strategy than Tishana, Voice of Thunder. He's probably most analagous to Azami, Lady of Scrolls with wizards, and since many blue wizards also happen to be merfolk, we'll likely see a lot of the same minions in the deck.

Hadana's Climb - Winged Temple of Orazca — Do you like Ezuri, Claw of Progress? What if he was able to turn into Xenagos, God of Revels? I like it. Each of these legendary flip enchantment/lands gives us our own personal mini-game and minor victory condition that we can celebrate no matter what happens later in the game.

Merfolk Mistbinder — Are you making a merfolk tribal deck? Does it have both blue and green? If so, then here's a card that you don't have to spend any mental effort on debating whether or not to use it. Just put it in the deck. Done.

White/Black Vampires

Legion Lieutenant - Speaking of 2 CMC tribal auto-includes... Are you brewing vampires and using both white and black? In the deck. Done. Moving on.

Elenda, the Dusk Rose - Note: Elendra is a different word. This card does not have her own Glen.

Like Child of Alara or Kamigawa dragons like Kokusho, the Evening Star who do something cool when they die, Elenda does have to die and go to the graveyard instead of the command zone in order to trigger the last ability. In the 99 of Edgar Markov this won't matter, but as a commander it's something to consider. Maybe add some reanimation tricks so your deck can still function after Elenda is buried. Reminder: Yahenni, Undying Partisan is both a vampire and a sacrifice outlet to kill Elenda. Just saying.

Profane Procession - Tomb of the Dusk Rose - Aside from the reference to Elenda in the Tomb's name, this one isn't specific to a vampire theme. It's more along the lines of Ashiok, Nightmare Weaver or Lord of the Void, which can take opponent creature cards out of the game and maybe get the option to use those threats on our own board. While some readers might focus on the fact that it takes a total of 18 mana to turn this into a land with benefits, consider whether or not it would still be worth it if this was just a 3 CMC enchantment that can repeatedly Unmake for 5 mana instead of 3. Pretend the land flip side doesn't exist. Is the card still playable? Possibly.

Black/Green Reanimate

Journey to Eternity - Atzal, Cave of Eternity - This card is good. Totem armor that easily turns into repeatable reanimation is something that every black/green commander would love to have.

Jungle Creeper - Would I pay 3 and black green to return a creature of my choice to the battlefield? Yes I would. Would I choose Jungle Creeper to go to my hand instead of the field? No I would not. Pass.

Red/White Deathtrap?

Path of Mettle - Metzali, Tower of Triumph - In the right deck, this is one of the easier Rivals flip cards to transform. Boros (and Naya) tends to prefer high end creatures with combat keywords on them. Metzali's abilities are decent. Note that the last ability can be used on opponent turns even if none of those creatures attacked you, so there are potential political benefits by offering to help a defending player and securing some kind of deal that way.

Red/Black Angrath

Angrath, the Flame-Chained - Discard and burn, Threaten and maybe sacrifice, or burn the graveyards. I like all of these abilities.

Angrath, Minotaur Pirate - Mass ping a player, reanimate a pirate, or demolish the single player who has the biggest army. The second ability implies a pirate tribal deck.

Angrath's Fury - The cards that tutor for a specific planeswalker work best when the planeswalker is actually good, and unfortunately the planeswalker deck versions just aren't as good as their counterparts in the related set.

Naya Dinosaurs

Huatli, Radiant Champion - While Huatli is thematically associated with dinosaurs, this planeswalker may be better suited to a more generalized token deck. Going wide lets you go big. Green/white are the right colors for mass token swarms, so I expect this will show up in the 99 of a lot of non-dinosaur decks.

Atzocan Seer - This expensive mana dork probably isn't worth 3 CMC if you aren't running dinosaur tribal, but if you are then of course this goes in a lot of decks.

Time to poop on some dinosaurs...

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Raging Regisaur - A four CMC single-target pinger is a bit underwhelming. It could help you activate your other enrage dinosaurs, but it won't see much play outside of dinosaur tribal decks.

Relentless Raptor - Two mana for a 3/3 with vigilance seems ok. But just ok.

Siegehorn Ceratops - Since this enrage dinosaur only puts counters on itself, EDH doesn't seem like the best format for it. Look for it to show up in the lesser quality but inexplicably more popular formats.

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Zacama, Primal Calamity - Untapping all your lands is very powerful. However, nine mana is a tall order for any commander, and the mass real estate untapping won't work with non-cast summoning cheats like Mayael the Anima or Green Sun's Zenith. Green allows some heavy mana ramp to offset the casting threshold, and once this is on the field then watch your opponents' artifacts and enchantments explode. Also, this is a dinosaur with three heads. If you make a four or five color deck, you could have The Mimeoplasm with its T-Rex arm copy Zacama and then it would have four dinosaur heads. FOUR DINOSAUR HEADS! Make it happen, people.

Blue/White Flyers

Azor, the Lawbringer - Oh look, a blue/white card that stops opponents from doing things on their turn when it enters the battlefield. And it's in the colors that happen to Flicker its own creatures so it can shut down everyone's instants and sorceries every turn. Oh, and why not cast Sphinx's Revelation over and over again? What could go wrong? Roon of the Hidden Realm and Brago, King Eternal decks should take note.

Resplendent Griffin - Unless ascend is very important to your deck, just use Ishai, Ojutai Dragonspeaker instead. Pass.

Grixis Pirates

Of course, Admiral Beckett Brass decks will be including all of the following...

Deadeye Brawler - This is probably the least useful multicolored pirate in this set, but it's still not terrible with deathtouch and eventual Curiosity.

Dire Fleet Neckbreaker - Good in Brass or Angrath-themed pirate decks. Not so good for Vraska, Relic Seeker. Maybe you could fake everyone out with a Vial Smasher the Fierce / Thrasios, Triton Hero deck, but it's just pirate tribal to include both the Brass and Vraska contingents. Surprise!

Protean Raider - Most clones cost at least four mana to cast, unless they have some mechanical drawback complication. Attacking with a creature isn't a difficult prerequisite, but it does imply that this won't come out until your second main phase.

Storm Fleet Sprinter - Three mana for a hasty unblockable 2/2 is a good deal, and a good vehicle for applying auras or equipment to opponent faces. What a nice Quietus Spike you have there!

Captain's Hook - Menace is an underrated ability, and this is cheaper to equip than Chitinous Cloak. I'm not sure what deck wants to have more pirates that isn't already running loads of pirates, but here's one more.

Treasure

Gleaming Barrier - Not amazing, but it does make a treasure...

Storm the Vault - Vault of Catlacan - Both sides of this card are very good. With this set bringing more Treasure-producing cards in blue/red/black, a Revel In Riches instant-win combo deck becomes more feasible, with or without Hellkite Tyrant as a backup. We could do this pseudo-thematically with Admiral Beckett Brass. On the other hand, we could come to our senses and use Breya, Etherium Shaper instead, since she actually has useful things to do with a pile of Treasure artifact tokens and she probably has a few more artifacts in her deck for making Tolarian Catlacan mana.

The Kitchen Sink

The Immortal Sun - This does a little bit of everything and only does it for you, as long as you aren't using any planeswalkers. Wherever there is a meta that is being oppressed by the multitude of Atraxa, Praetors' Voice superfriends decks, the players will fight back by jamming this card in their decks.

Silent Gravestone - This feels like a deluxe Relic of Progenitus. It costs more to cantrip and clear all the graveyards, but unlike the Relic it starts doing heavy lifting as soon as it appears.

Awakened Amalgam - I don't know where this card goes in EDH. Multi-color artifacts? Reaper King wants scarecrows instead of golems. Ramos, Dragon Engine wants spells with colors in the mana cost. Breya, Etherium Shaper wants cheaper artifacts to sacrifice. This is ultimately a vanilla creature with increasing power and toughness, and vanilla creatures rightfully get cut from most EDH brews. Pass.

Golden Guardian - Gold-Forge Garrison - At first glance, this card seems confusing and unimpressive, but if you are making a theme deck around the movie Hellboy 2 then it will be a star.

Arch of Orazca - Six mana to draw one card is a bit too steep a cost. This may show up in decks that have a heavy emphasis on cards with ascend...?

Orazca Relic - This reminds me of Manalith, in the sense that there are many other better 3 CMC mana rocks. Why run this instead of Commander's Sphere? (If you are not Mazirek, Kraul Death Priest)

Azor's Gateway - Sanctum of the Sun - The most difficult flip condition also has the biggest payoff. If you have any deck built around your favorite X spell (for example Villainous Wealth, Epic Experiment, or Torment of Hailfire), then you can add this win enabler no matter what colors the deck is using. I predict that the patient casual players who are still running Brain in a Jar will start trying this card instead.