Given that this isn't a "hidden gems" thread, and literally underused, I've given my list of cards comparable to power level. So although some are played in literally thousands of decks, they still represent a disproportional amount of play for what they can do.
The numbers are from EDHREC. I've ordered these from the least played to most.
Riptide Shapeshifter (150 decks)
This can be an extremely powerful and versatile card, but it requires a special kind of way of looking at your deck to figure out it's true worth. You need to see numbers of creature types to figure out if it's going to be good for you. But there are going to be thousands of decks that this is great in that people just are going to be unaware about. If you have lots of one-off creature types then you can use this at any stage of the game to get that creature. Think Praetor (
Jin-Gitaxias, Core Augur), Elephant (
Terastodon), Djinn (
Tidespout Tyrant), Gorgon (
Damia, Sage of Stone), Elder (
Nezahal, Primal Tide), Avatar (
Diluvian Primordial) as examples of creatures types that are easily played as singles in your deck.
It is mana intensive but the ability to use it at instant speed means that you can catch people unaware of what you can do in response to plays.
Kaho, Minamo Historian (226 decks)
My first foray into posting threads for commander was actually for this gal, and about being one part of your 99 and not meaning as your commander. You can check out the article still on MTGSalvation =>
Kaho, Minamo Historian, the best all purpose tutor not in black.
She is just incredible under utilized.
Vanish into Memory (371 decks)
If you've never played with or against this card then you'll have to trust me that the tempo swing for four mana is incredible. There is almost always a big target for it in multiplayer games, so your are easily drawing 5 cards (or more). It can be used in several different ways. To remove an opponents creature that may be causing problems at that moment in time, or you can use it to save one of your own creatures.
Discarding cards isn't really a downside considering you get to filter through so many cards.
I'd play this card over
Fact or Fiction (24036 decks) in an Azorius color paired deck any day of the week as it offer so much versatility.
Portcullis (372 decks)
This card causes so many problems to so many decks in hard to fathom ways. Basically as soon as you cast it no more creatures hit the battlefield. OK, so you're thinking "well I just cast creatures out and in no time at all somebody will remove it".
So people just cast their creatures over the next couple of turns as usual. But already this is a huge tempo swing. Those creatures have not effected the game. There is also no surprise value. Everybody gets to see what is coming up. Now this in turn will start to make opponents hesitant about actually removing it. The player that
does draw removal for it, might be scared off what other opponents have put under it. So they just stop casting creatures into it and don't use their removal on it.
For the player who cast it, you're probably creature light deck, and it buys you time to draw into mass creature removal. So you get the maximum amount of value when you cast removal. Otherwise you're potentially being pressured into casting removal on much smaller amount of creatures because you are still being pressured.
This is very close to
Humility but colorless (so playable in any deck). And if you've played against/with
Humility you'll know how much it effects the game.
Hunting Grounds (390 decks)
Has to be in the right build, but make sure you put it on your "is it potential to play" list anytime you have a creature deck with Selesnya in your color pie.
Null Brooch (464 decks)
This discard seems scary, but a counterspell every turn when you have enough of a board presence often locks up games. Plus it has the effect that each opponent doesn't want to play their big spells into it, so you're actually holding off way more spells than you first think. It's not like it's actually just countering a single spell each turn round. It's preventing players from casting
any relevant spells often.
For any non-blue deck that wants more control over power plays.
Kalemne's Captain (422 decks)
I wouldn't say a shoe-in, but way better than number of decks reflect. At the end of the day it's still a 5/5 for 5 mana, and then going forward you can hold up the mana to threaten the mass removal. It's not as good as
Bane of Progress as it's more mana intensive, but you can use it as a political tool, holding off using it if opponents don't get too frisky with you or what artifacts or enchantments they play.
Wheel of Sun and Moon (522 decks)
There is a lot going on with this card, and it does require special thinking about it can work for your deck. But the easy mode is just enchanting a graveyard strategy player and shutting them completely off.
But you can play it on yourself if you've got special ways to reuse certain cards in your deck. Too many numerous ways to mention any, but keep this card in mind, especially if graveyard strategies are popular among your meta (I mean what meta doesn't have them!?)
Mystic Barrier (899 decks)
Probably gaining some stock as people figure out
Pramikon, Sky Rampart ability through playing with and against. But
Mystic Barrier is still better as you can keep changing directions, and honesty holds up as my favorite "casual" card to play in commander. Every time I play it it effects that game more than almost any other card that isn't directly winning the game. It's just surprisingly good and fun. The way you can dictate whats going on in the game makes it one of the most political cards without needing to talk to your opponents. You get to decide how the action plays out.
Experimental Frenzy (917 decks)
Obviously a well known card, but underrepresented for deck that have red and have a lack of draw.
Magus of the Future (992 decks)
Same as
Experimental Frenzy in that it's one of the most powerful effects literally in the game of Magic. This gets overshadowed by it's enchantment cousin
Future Sight, and for good reason as creatures are more fragile than enchantments normally. But still it has the same effect and simply better than
Oracle of Mul Daya (people will argue about playing two lands), which people just can't afford $$ moneywise. This is a $2 card and if you've got a mana base than supports triple blue, then you should really look to this as a potential card.
Patron of the Orochi (1036 decks)
My very first commander, so holds a special place for me. But I'm talking about a card in your 99. It's really really really powerful. Not as good as
Seedborn Muse, sure, but a second
Seedborn Muse effect can be understood by most.
Will Kenrith (1091 decks)
I think still one of the most overlooked planeswalkers for power in your 99. A lot maybe because people are not playing in red, so they feel like they are missing out on the Rowan partner value. But by himself he is one of the most powerful planewalkers in the game, so do not be distracted by that, play him on his ability to shut down creatures, draw cards and cost reduction, and incredible emblem in the right decks.
Dreamscape Artist (1264 decks)
In the blue which does not have much access to land ramp,
Dreamscape Artist can offer you ramp every turn. I think the "3" mana puts people off, but the lands come into play untapped, so really this card only costs you
1 mana to use. It does have card disadvantage from hand, but obviously with access to more mana you can play out spells that draw you cards more readily. Also good for graveyard strategy decks as well.
Uncage the Menagerie (1451 decks)
I think this one will be down to complexity of figuring out how good it is given your deck. But this is one hell of an action card. It scales, so early on you can simply cast it for 3 mana to get a one drop if requiring mana fixing. But then you can cast it for 5 mana later on in the game and get 3 x 3 cmc creatures, which I bet you is going to get you perfect action for that stage of the game.
Really this just comes down to figuring out your converted mana costs you lazy bums!!
Kira, Great Glass-Spinner (1506 decks)
In many ways just gives your creatures hexproof, as opponents don't want to waste a spell to get through it. Have you guys heard of hexproof? Do you think hexproof on your creatures is worth it? Ha ha tricked you, that was a rhetorical question, of course it is.
Medomai the Ageless (1878 decks)
Starting to climb up with popularity, but still an underrated card for what it actually does. Extra turns on legs. Will take over a game more easily than you think.
I mean if you compare it to other much more popular 6 drops, like Sun Titan (27496 decks) and Grave Titan (12301 decks), this guy has a way higher ceiling on potentially winning games.
Slate of Ancestry (2099 decks)
Again probably the "discard" scares people off a little, but as an artifact this should be in way more decks. Going wide with creatures is one of the most popular themes in commander, so should be in way more decks. Just simply an oversight by deck builders. The discard doesn't matter when you are getting exponentially more cards.
Walking Atlas (2156 decks)
One of my "tech" cards for most draw decks outside of green. Really underused card still as it's often an extra land drop every turn for decks that can consistently draw cards.
Faerie Artisans (2732 decks)
The most popular card on my list, but I still might say the most underplayed for power. Honestly this card if not answered within a few turns, just takes over the game. It's hard to put a value on this card when you look at it or put it into your deck, because you don't know what the outcome is right? But trust me once you're getting a version of every opponents creatures, the value is just overwhelming. Every ETB/LTB effect your opponents are playing you get also. You have a guaranteed blocker each turn to put in the way of attacks. Probably the card that always over-performed for me every time I've put it onto the battlefield.
The good thing is that normally it takes a while for opponents to remove it as well, because there is no quantifiable amount of value when you cast it. It's just when opponents figure out how ridiculous good it is after already getting value that the might have to Demonic Tutor specially for removal, it's that good.