doctorhydrogen

I'd run both. Doubles your chances to draw one, and even if you pull both having two in play (or on in hand in reserve) isn't a bad thing.

Also, Ophiomancer kicks a token every upkeep, not just yours. It can get out of hand fast in a multiplayer game if you have a way to sacc one every turn.

Hinder, Dissipate and Dissolve are all the same CMC as Cancel, but better :)

All those black mana symbols would probably like Nykthos, Shrine to Nyx.

Maybe it's overkill but I'd think Dicate of Erebos would also fit nicely.

If you're running Grave Pack imo you should also have room for a Dictate of Erebos.

If people are saccing a lot of creatures, Grim Feast could give you a lot of health and Deathreap Ritual could draw you a lot of cards.

Urborg, Tomb of Yawgmoth should be fairly cheap in the coming weeks, and it's amazing mana fixing.

Regrowth is the same cmc as Treasured Find and it doesn't exile itself if you have a way to get it back.

Lotta black mana symbols that would like Nykthos, Shrine to Nyx.

Cover of Darkness is solid in vampire tribal.

Unless you're on a super tight budget Hero's Downfall > Murder

Cuombajj Witches seem like a good way to remove counters from your own planeswalkers. Is there something I'm missing?

Glare of Subdual can lock people down hard in a Ghave deck.

Quicksilver Fountain is a beast in mono-blue, as is Back to Basics.

Maybe find room for Spin into Myth. The ability to put a commander or touble creature on the bottom of a library can be invaluable.

Quicksilver Fountain is a beast in mono-blue.

If you're truly playing competitive I'd say you need a Maze of Ith, a Stripe Mine, and probably a Wasteland (or at least a Ghost Quarter or Tectonic Edge to save cash).

For one mana more than Journey to Nowhere, Banishing Light will hit planeswalkers, artifacts and enchantments. Seems worth it to me. I'd probably run Lignify over Journey, too, as it keeps commanders stuck on the field.

And then pray they'll play a second game with you after. Stax decks are great in a competitive meta, but when you're effing around for fun with friends it's not much fun watching the guy with the stax deck magicbate while you sit there unable to do anything for ten turns until it's time to shuffle it up again.

I wouldn't say it's ineffective. I personally don't run it, but I can see situations where there are cards you absolutely do not want to see hit the board.

The biggest problem for me with Nevermore is the fact that it's a bit of a dick card. Dick cards are totally fine (and necessary) in competitive environments, but I personally wouldn't want to sit down to play a game with friends and have a turn two Nevermore come out preventing me from ever playing my commander unless you have an answer (which red and black often times do not). As such, I wouldn't do it to someone else who is a friend I play with for fun. YMMV there.

Citanul Flute might be good, too, you've got a lot of low cost goblins. 1 mana to tutor up one of your 1 cmc goblins per turn seems like good value.

manabasecrafter.com is a fantastic way to see what the lands are that work for any given commander colors.

You have Murderous Redcap entered twice.

I'd consider one or two ways to better hit indestructible stuff (Theros gods are everywhere). Maybe swapping Dogpile for Sever the Bloodlines or something. I like Sever because it doubles as a way to handle a bunch of tokens, and you can flash it back late game.

Urborg Tomb of Yawgmoth is amazing fixing. I wouldn't get one now, but it'll be a sub ten dollar card in two weeks and IMO every black deck should have one.

Get a Chaos Warp if you can, it's one of the few ways you can handle a problem enchantment.

Mana Echoes is pretty great in Goblin tribal.

Auntie's Hovel, Graven Cairns, Blackcleave Cliffs, and Shadowblood Ridge are all sub-ten dollar dual, and I'd run all if possible, especially over Urborg Volcano, Tresserhorn Sinks, and maybe Meteor Crater.

Thinks all deck need at LEAST three each imo:

1. Draw: You need some way to draw cards. White doesn't have a ton of options, but if has a few. Mind's Eye is amazing, well of Lost Dreams is great if you have good life gain, and Seer's Sundial works as well. You can almost never have enough draw.

2. Targeted removal: For artifacts, creatures, enchantments, and to a lesser extent lands, and if at all possible things that exile or tuck vs. just send to the graveyard. There's so many graveyard shenanigans in EDH that sending something to the yard just means you'll see it thirty seconds later more often than not, and straight up destruction doesn't work on Theros gods, Avacyn, Tajic, any artifact deck with a Darksteel Forge (i.e. every single artifact deck). You're doing well there so far, though I'd replace Cursebreak with something like Revoke Existence since it exiles and hits both enchantments AND artifacts. I like a Strip Mine in all decks to deal with an annoying Maze of Ith or Serra's Sanctum or Nykthos, and at five bucks-ish it's pretty affordable, but Ghost Quarter works fine, too. I run both.

3. Sweepers: Ways to reset the board state when things get out of control in someone else's favor. White has a ton of options here. Austere Command has a lot of flexibility, Wrath of God is cheap, Phyrexian Rebirth kicks you a token to start the reset off in your favor, Rout is instant speed, etc.

Crackdown and Mass Calcify are great in mono-white, as is Pearl Medallion.

Sapphire Medallion would work well here, too.

Wheel of Sun and Moon lets you slide all your creatures that die back into the library so you can then grab them with Sisay again.

All those green mana symbols would probably love a Nykthos, Shrine to Nyx.