I am a sucker for counters and was gaga over the White cards. The Blue cards are pretty good too.
Cruel Entertainment: Very interesting multiplayer card. I guess this is a good way to force two of your opponents to weaken each other.
Curse of Vengeance: Nice addition to the Curse cycle from Innistrad and Dark Ascension. It's only a one drop.... nice. That can be a lot of spells casts, you just need to be sure that the cursed player will die before you do!
Curtain's Call: It's an instant, and with five opponents, it's a one drop. I am loving Undaunted.
Magus of the Will: Very interesting card. In the late game in Commander, say you have ten mana available, you can cast this mid game and if it is not removed, you have seven mana to cast cards from your graveyard. That is great.
Parting Thoughts: A somewhat limited card. The creature you destroy better have counters! True, if it doesn't have counters, it is well costed (similar to Murder, at 1 Black Black).
Army of the Damned: Fun junk mythic from Innistrad. In Commander, it is a much more possible play.
Bane of the Living: From Legions. Clever board wipe.
Beacon of Unrest: Great reprint. It's versatile. I want to play it.
Brutal Hordechief: I had a lot of fun playing this card in Standard. It goes well with Hellrider from Dark Ascension.
Executioner's Capsule: Somewhat limited, but with many players, someone will have a nonblack creature you want to destroy.
Festercreep: Very good against a zillion 1/1 tokens. Otherwise, somewhat limited. Now, if you make it the source of counters you can add with other cards, you can remove multiple counters for a bigger effect.
Ghastly Conscription: Great effect in Commander. When done right and with luck, it should place you in a really strong position in comparison to all other players, and it will make you the table's target!
Guiltfeeder: Nice effect against the correct player. It's a mid game play, and some of your opponents will have a board full of blockers. I wonder how effective this can be.
In Garruk's Wake: Nice late game effect to clear out some of the last players still standing.
Languish: Solid is solid. It should be very effective in Commander.
Necroplasm: I have never played this card. It reads strong. If there are lots of one mana and two mana creatures on the board, someone will have to remove this or else. On the flip side, it can have a limited effect if it is removing three mana creatures when everything on the board is at a lower mana cost. Dredge still puzzles me. Someday, I would like to play a dredge deck and understand it well.
Sangromancer: Awesome card to boost above the Languish threshold.
Waste Not: A community design, and a really fun card in any format. I am not seeing enough cards that cause opponents to discard to make it really powerful when played only with these cards.
Wight of Precinct Six: This can get insanely big with a table full of opponents. I want to see that!