doctorhydrogen

Vile Consumption is kind of great in Oloro, especially if you face any token decks like I do. There are metas where it wouldn't be useful, and yours may be one, but in mine it wrecks havoc.

I personally run both. The 5% of the time that having two creates a worthless card is a reasonable downside when the upside is double the chances to pull a card draw engine.

I was placing a singles order tonight, and threw Maralen, Sickening Dreams, Ad Nauseum, and Dark Sphere into the list. I'd never play the deck seriously, but three bucks is worth the lolz even if I just do it once.

Cover of Darkness is fantastic in a vamp tribal deck where you want to get as many hits in as possible to build counters.

The cost on Fetches are a pain. I'm not running any either just because I wasn't playing at Zendikar and I can't justify the cost to buy them now, same with ABUR duals, so I know exactly where you're coming from.

Some of the filter lands are fairly reasonably priced (I think Sungrass Prairie is under two bucks) and Krosan Verge, while not amazing, is probably worth considering at the fifty cents it costs.

Meteor Crater is decent in a three color deck and it's around a buck.

Storm Herd would be a fun win con, especially when you're sitting at 140 health or something.

I've had good luck with Zur's Weirding in Oloro deck, especially once I have an alternate card draw in place and some life gain rolling. You can basically prevent anyone from drawing anything that will hurt you. It's powerful, but also janky enough that everyone at the table tends to be okay with it when it works.

Trade Secrets is solid and would be in a 125 card deck, but I just can't ever find room for it in a 100 card deck. It's probably much stronger in solo commander where you don't care that it just hits one person, but I tend to play almost exclusively 4-5 player games, so I myself go for cards that hit everyone. YMMV on that.

Privileged Position wouldn't be legal given your general's colors even though you can cast it.

Sanguine is pretty fantastic in a Sapling deck since most of the time you'll be gaining life each turn with his on-attack ability.

Strionic Resonator can be used to double up Saplin's ability.

Abundance is nice with Sylvan Library as it lets you keep all three cards. It's useful even when the Library isn't out.

Is Crucible of Worlds worthwhile with no fetches?

Regrowth is slightly easier to cast than Treasured Find, and doesn't get exiled after use. I myself would just run both :)

Garruk, Caller of Beasts and Wild Pair seem to be worth pondering in a deck this creature heavy.

Generically I'd say you need a few ways to protect Nekusar. At least at my table everyone guns for him the second he hits the table. He's not a cheap Commander, either, so going from 5 to 7 to 9 to 11 mana to continually recast him after he eats a Beast Within then a Swords to Plowshares then a Murder then a Dreadbore isn't much fun. I'd say get at least a couple ways to keep him safe. Lightning Greaves, Swiftfoot Boots and Whispersilk Cloak would be my top choices.

-- Creatures I would strongly consider:

Viseling: People are going to pretty often have 7 cards in hand. Dealing 3 damage every upkeep seems a solid investment.

Kederekt Parasite: One damage per card a person draws is huge in this deck

Psychosis Crawler: One damage to each person per card you draw is huge

Jace's Archivist: Wheel effects are MASSIVE in a Nekusar deck. If one person has seven cards in hand and you tap this bad boy, every opponent takes seven damage. If Kederekt Parasite is in play they each take seven more. If you have Psychosis Crawler in play they take another seven.

-- Artifacts I would strongly consider:

Temple Bell: I like this over Howling Mine (or at least in addition to Howling Mine). The reason is if you drop a Mine in a four player game you don't get to draw from it until next turn and it doesn't hurt anyone until next turn. Temple Bell on the other hand you can pretty much guarantee you make everyone draw immediately and you can get a card from it, too.

Teferi's Puzzle Box: Same as Jace's Archivist above, you almost guarantee people take seven damage per upkeep, and if you have Kederekt Parasite in play they're take 14.

-- Enchantments I would strongly consider:

Arcane Laboratory: The problem with making everyone draw a ton of cards is it means they draw a ton of cards :) That's a lot of chances to draw combo pieces, answers to problems, etc. Arcane Laboratory minimizes the amount of damage someone can do to you with the dozen cards you just made them draw.

Bloodchief Ascension: You know all those wheel effects like Jace's Archivist or Teferi's Puzzle Box above? This adds ANOTHER 14 damage to each player when they have to discard seven to draw seven.

Phyrexian Tyranny: Make 'em take another 2 damage per draw

Words of War: Whenever you draw, spend 1 to deal 2 damage to someone or some creature.

-- Instants I would strongly consider:

Wheel and Deal: Why make one person draw cards and take damage with Blue Sun's Zenith when you can use Wheel and Deal and make EVERYONE do it

-- Sorceries I would strongly consider:

Minds Aglow, Skyscribing: Same as Wheel and Deal in that they hit everyone

Molten Psyche, Reforge the Soul, Time Reversal, Whispering Madness, Windfall, Winds of Change: Wheel everyone's hand full

I'm a big fan of Dolmen Gate in Kaalia, because it lets you attack (and play a creature) at times when doing so would normally be suicidal.

Nykthos, Shrine of Nyx would seem to be a great addition to a deck that's probably going to have 10+ green mana symbols in play by turn 5.

Abundance will let you keep all three cards from Sylvan Library, and it's pretty great even without the library out.

Triumph of Ferocity might be useful considering the big creatures you have.

With nearly 1/3 of your deck being creatures Lurking Predators will probably get you a lot of freebies. I have a friend who runs it in a deck with 32 creatures, and in a 4 player game he sometimes gets 4-5 creatures into play before it's even his turn again.

I'm not a huge fan of instants or sorcerys that don't do something that seriously impacts the board or saves your butt like being able to Beast Within a Sylvan Primordial or Deglamer a Theros God. Is it really worth a slot for Giant Growth for a one-time bump when you could instead use Blanchwood Armor and maybe give your creature a permanent +7/+7 or something? Keen Sense has the same mana cost as Warrior's Lessons and stays in play, Alpha Authority gives some evasion and lasts beyond the turn unlike Ranger's Guile. Or even better use Equipment that can be moved from creature to creature. Whispersilk Cloak, Lightning Greaves, Swiftfoot Boots all give protection and other things.

With this many big fatties maybe consider Wild Pair. The only thing better than dropping some big 6/6 fatass is dropping a second one for free next to it.

I'd think you'd want a Nykthos in there, too, given how many green mana symbols you'll have in play.

Lands:

Given the limited amount of fetchs or lands with sacc effects you run Crucible of Worlds seems unnecessary.

I think you're running too many ETB Tapped lands, which also simultaneously opens you up to Blood Moon. I personally would clean out the Gates, maybe a few others and just go with a few basics.

Exotic Orchard is nice in three color, especially if you're playing multi-player. You're almost always going to have all three colors available.

Dryad Arbor always dies to a board wipe at really crappy times in my meta, so much so that everyone quit playing it even in decks where it really made sense. YMMV there.

EDH is very meta-dependent. I myself play almost exclusively with the same half-dozen players who have consistently understood and established deck building and play styles. Your meta may shift more regarding deck building and play styles or it may be wildly different than mine, so bear in mind that my comments come from how your deck would fare at the table I play at as they may not apply to the table you play at.

My meta runs a lot of board wipes and a fair amount of spot removal. As a such, any deck with a commander that is key to the deck winning needs to protect that commander. At the table I play at Rafiq would simply never deal the damage he'd have to deal with one pair of Lightning Greaves, a Flickerform and a Bear Umbra for protection. Personally I'd find a way to slot in Whispersilk Cloak at least. It's one more way to protect him, and unblockable is fantastic with a voltron commander.

I'd replace Slice in Twain with either Return to Dust (being able to hit two artifacts, enchantments or Theros gods is much more valuable to me than drawing a single card) or Krosan Grip (if you see a lot of Sensai Divining Tops).

Brainstorm is nice, but I wouldn't run it over something that gets me more cards more often, like Rhystic Study. Given your Voltron build you could even go with an on-damage card draw engine like Curiousity or Ophidian Eye or Coastal Piracy or Mask of Memory.

Thassa would be a good fit I think. Make Rafiq unblockable, scry each turn, and it's all attached to a big, indestructible butt if you hit devotion. But even if you don't scrying and making Rafiq unblockable seems worth the casting cost.

Now that I think about it maybe Dolmen Gate over Recon. It would accomplish the same thing, but still let your creatures deal damage.

I like Temple Bell over Howling Mine becaue Bell it always going to let you draw a card. With Mine you run the risk of never getting a card yourself before someone else Disenchants it.

Black Vise & Viseling since people will tend to have full hands.

Teferi's Puzzle Box & Psychosis Crawler feel like auto-includes, Robber Fly might fit

Arcane Laboratory makes everyone less able to take advantage of the big fistfull of cards you're giving them

Bloodchief Ascension takes advantage of all the hand cycling

Wheel and Deal, Diminishing Returns are two more hand cycler

Reiterate, Reverberate, Twincast, Fork, & Increasing Vengeance would all let you double any hand cycler you cast

Not sure which of those I'd use, just making suggestions.

Interesting. I never thought of Tariel for a Shadowborn Apostle deck. i'm currently trying Sek'Kuar, Deathkeeper for mine but I'm having problems cutting down to 100. Tariel is interesting, though. Nice start.

Have you considered Citanul Flute? Yeah, it's five to play, but once it's in play you can tutor up an Apostle each turn for 1.