OUT OF DATE LIST. Pending updates.
First thing's first, let's talk about what the deck wants to do. The primary goal is to make the battlefield as hostile to creatures as possible. This is achieved through a variety of wraths and through Vhati's unique ability. One damage on a creature means he can tap to kill it. A single -1/-1 counter on a creature means he can tap to kill it. He's really fun to play for this reason.
The second goal is simply to throw some bombs around and beat people up.
That pretty much sums up the broad-stroke strategy of the deck, now let's get into specific cards. Many of these are probably self explanatory, but I included a short description of why they're good or why I play them regardless.
This list is outdated by several sets now. Pending updates.
CREATURES
Acidic Slime: One of green's best creatures. Versatile upon entering the battlefield, blocks well, can sneak in some damage.
Bloodgift Demon: This is a Phyrexian Arena on wings. Worth playing in pretty much any black deck.
Carnifex Demon: He's an all star in this deck. Blanket -1/-1 counters to set up Vhati's tap ability is sweet, and there's the corner case of getting multiple
Wickerbough Elder
activations.
Crypt Ghast: Mana doublers - Good. Mana doublers with extort - Incredible in multiplayer. Seriously.
Deathrite Shaman: Super versatile card. Targeted graveyard hate starting on the first turn, or a Birds of Paradise that's easier to cast. Plus the draining life.
Eternal Witness: Staple. Nothing new here. Gets stuff back for cheap.
Glissa Sunseeker
: First Strike works perfectly with Vhati, and there can never be enough artifact removal.
Glissa, the Traitor: Nobody can attack into this. Nobody can block this. Gets my artifacts back after a board wipe.
Harvester of Souls
: Turns Vhati into a card advantage machine. All wraths are now Decree of Pains. This guy is sweet.
Horobi, Death's Wail: Horobi is interesting. It can backfire very easily, but it also synergizes really well with Vhati, Desert, Shizo, Death's Storehouse, and more.
Krosan Tusker
: Instant speed, uncounterable Divination in green. Can be a 6/5 in a pinch. Staple without a doubt.
Massacre Wurm: This fella is a beating, plain and simple. He destroys tokens and works really well with the killing creatures theme of the deck.
Midnight Banshee
: Another blanket -1/-1 on a big body. Also eats a lopsided amount of removal for some reason.
Pestilence Demon: Easily my favorite creature in the deck. He's a gigantic flyer with the best possible ability to synergize with Vhati.
Plague Spitter
: Pestilence Demon's noble steed.
Rune-Scarred Demon: Black staple. Nothing to see here.
Scavenging Ooze: Thanks to M14 I finally got the super ooze. He snipes graveyards, gains some life, and gets huge.
Solemn Simulacrum: Goes in every deck ever made period.
Soul Snuffers
: Yet another blanket -1/-1 effect, this time upon entering the battlefield.
Wickerbough Elder
: Repeatable destruction that synergizes with the -1/-1 counter dudes. He's often a 3 for 1 or better. I don't know why anyone would play
Indrik Stomphowler
over the Elder. Same amount of mana for the same effect, Elder doesn't fold to Torpor Orb, etc.
Wurmcoil Engine: Efficiently costed deathtoucher that comes back for more upon dying. Lifelink is nice to gain back self-inflicted damage, which is an unfortunate subtheme in this deck.
ARTIFACTS
Basilisk Collar: Put this on Pestilence Demon for a fun time. Or just throw it on a beater to get some life back and dissuade blocks.
Darksteel Ingot: Multicolored mana rock staple.
Illusionist's Bracers: I toyed with adding this for a long time and decided to try it out when I got a foil copy. It's pretty wild.
Lightning Greaves: Goes in decks that have creatures and/or tap abilities.
Oblivion Stone: All star wrath effect. Gets rid of stuff, comes back with Glissa, the Traitor.
Relic of Progenitus: Shuts down reanimator, graveyard combos, etc.
Sol Ring: Nothing to say about this, except TURN TWO VHATI, YEAH!
Thornbite Staff: This can turn Vhati into a machine gun with something like Night of Souls' Betrayal out.
ENCHANTMENTS
Fevered Convulsions
: People often chuckle when I play this, but it's a really solid card once you get into the mid-late game. It's repeatable removal and a mana dump.
Grave Betrayal: Terrible in constructed. Terrible in limited. Awesome in EDH. Seriously, this thing is ridiculous.
Leyline of the Void: Anti-synergy with Grave Betrayal, but that's okay. This thing does way more work than any 4 mana enchantment should.
Night of Souls' Betrayal: The interaction between this enchantment and Vhati is what prompted me to make this deck in the first place. Tap, kill. Tap, kill. Tap, kill.
Pestilence: Repeatable pinging makes Vhati very happy. This is also a pseudo win condition in the late game.
Phyrexian Arena: One of the best turn three plays in black. I find myself tutoring for this enchantment all the time.
SORCERIES
Ashes to Ashes: Two for one removal. Exile instead of destroy. That's worth three mana and five life at sorcery speed.
Black Sun's Zenith: Sorcery speed wrath. Shuffles back in for multiple uses (but doesn't go to the graveyard for recursion).
Cultivate: Sorcery ramp over artifact ramp.
Decree of Pain: Sorcery speed wrath x2. Card advantage galore.
Demonic Tutor: Tutors are good.
Dregs of Sorrow
: Sorcery speed wrath x3 (well,kind of a wrath). More card advantage.
Explosive Vegetation: I can't play a green deck without this card. Simply impossible.
Kodama's Reach: I decided to put in land ramp over mana rocks for added resilience to O-Stone and Nev's Disk.
Mutilate: Sorcery speed wrath x4. Lots of swamps = lots of -1/-1
Plague Wind: Sorcery speed wrath x5. One sided!
Praetor's Counsel: The spell that never resolves. This is countered extremely often, and for good reason. It's a sweet card.
Primal Command: Very versatile, as the commands tend to be. The creature tutor is my most-played mode, and the others are entirely dependent on the board state.
Promise of Power
: Why can't I hold all these cards? Oh, and here's a gigantic flying demon as well. This thing is, as the name suggests, powerful.
Regrowth: Another green card I have trouble leaving out of a deck. I never feel bad about having this card in hand.
Skyshroud Claim: Even though this deck is heavy on black cards, Skyshroud Claim is solid ramp. It fetches shocks too.
Syphon Mind: Card draw/discard that scales up hard in multiplayer. It has the potential to piss people off, but if you're playing the deck correctly, they won't be able to do anything about it.
INSTANTS
Abrupt Decay: There are a surprising amount of problem permanents that have low converted mana costs. This card shuts them down and is very tough to stop.
Beast Within: Staple all the way. Instant speed vindicate with a token that will probably not stay on the board long against Vhati.
Darkblast: Bold statement incoming: this is the best card in the deck. I've got a story that shows just how powerful Darkblast is. My opponent played Ulamog, the Infinite Gyre and blew up someone's random combo piece. Everyone panicked because Ulamog is scary. Opponent went to swing with the Ulamog (which had haste for some reason that doesn't matter to the story), and upon entering combat, I played Darkblast and responded to my own spell by tapping vhati, making Ulamog's toughness 1. Ulamog bit the dust. TL;DR - Darkblast kills eldrazi without breaking a sweat.
Krosan Grip: If you're playing green, play this card. It's only three mana, but it's a bomb against... pretty much every combo deck.
Putrefy: Versatile removal at instant speed.
Slaughter
: There's never enough repeatable removal in EDH. Especially when the buyback only requires paying life, not mana.
Slice in Twain
: Artifact/enchantment destruction that replaces itself. Well worth the four mana investment.
Sudden Spoiling: Is somebody comboing off with creatures? Is somebody swinging for lethal damage? NOPE.
PLANESWALKERS
Liliana of the Dark Realms: This deck is primarily black, so Liliana is really powerful here. Consistently making land drops is reason enough to play her.
Vraska the Unseen
: Nothing feels better than killing someone with Assassin tokens. Destroying permanents is nice too, I guess.
LANDS
Bojuka Bog: Black Staple.
Desert: This has hilarious synergy with Vhati. People generally dismiss Desert until they get blown out by it.
Evolving Wilds: Budget multicolored land. This makes opening hands a lot easier to keep when colors are tough.
Forest: Can't play green without them.
Golgari Rot Farm: Budget multicolored land x2. I love the karoos.
Grim Backwoods: Usually just a colorless land, but when things are dying and I've got mana up it's nice.
Overgrown Tomb: Because I can't afford a Bayou.
Shizo, Death's Storehouse: Sweet synergy with Horobi, Death's Wail.
Strip Mine: A lot of people play broken lands that terrify me, so I play Strip Mine to feel safe.
Swamp: Black staple.
Tainted Wood
: This is almost always a Bayou with no drawback.
Terramorphic Expanse: Budget multicolored land x3. See Evolving Wilds.
And that's all, folks! If you actually took the time to read through all that, you're awesome. If you didn't, you're probably still awesome. While I am no longer in the deck-building phase for this list, I am always open to suggestions. I hope you enjoyed this rundown of my favorite EDH deck!