Damn I like your list a lot! I am on my phone right now, so I will need to wait before to playtest, but I actually find yours way better than mine. The idea in mine was not to tutor Ad Nauseam only, but to use the commander as a way to up the storm count easier, and the deck can work better without the commander than yours I think... what if you face a Null Rod or Stony Silence???

I will playtest both later on today to see what is going on and tell you about it after!

Ok, so I goldfished a bit with your list, and we are winning on average turn 4/5. I think you could add Ebon Stronghold over a Swamp for the possible mana acceleration. I would also go with Grim Monolith, as it is another mana positive rock, and sometimes 1 mana is the only thing you need to win a turn earlier. Dark Confidant would be another good creature to continue drawing early to draw into something like ramp, and it could be sacrificed later on. I would like it over Reassembling Skeleton, since I am not really using the ability to reanimate for further sacrifice because I need to keep every mana I need, mana is so thight on turn 3/4/5...

As strange as it may seem, I would also cut Mishra's Workshop, because the opener would require a lot of artifacts to make it work, it doesnt help you to cast your commander faster. Once I was stuck with this in hand and was missing a single mana to cast the commander, and I was hoping it would be another land... I would also replace a basic land by Peat Bogfor further acceleration, since it can help you cast your commander faster and it can tap twice, which should not be a problem since after two turns tapping it you should be in your winning turn already.

I would also cut both Contaminationand Infernal Darkness, as they play against your gameplan. Yes they slow opponents down, but the idea here is to play your commander as fast as possible to combo earlier. It would make lands such as Ancient Tomb tap for less, which is bad, you would need to invest mana to keep it alive (which is bad) or you would need to sacrifice creatures to keep it alive, which also is bad since you want to have those creatures available to sacrifice for your commander's ability. I would go for more speed, so Grim Monolithand Dark Confidant, a mana positive rock and a small creatures that could come down early, help you draw faster into ramp pieces, and could be sacrificed during your combo turn. This would also lower your average CMC in case or Ad Nauseamplay, which is not bad also.

To prevent your life total, I would think about cutting fetches. They are not of that much use, since deck thinning is so small in a 99 cards deck, and you would only get basics. I would replace them with basic lands, it would preserve you some life (they are not played in storm decks such as ANT Sidisi because you want to keep as most life as possible for AdNaus, it also is the case here).

+Ebon Stronghold

+Grim Monolith

+Dark Confidant

+Peat Bog

+Swampx3

-Mishra's Workshop

-Contamination

-Infernal Darkness

-Marsh Flats

-Polluted Delta

-Bloodstained Mire

-Verdant Catacombs

Woops, forget what I said about Dark Confidantit was already in here. In replacement for the suggestion I did I would slot in Soldevi Adnate, since it can sacrifice creatures you already have in play or useless mana rocks like Grim Monolith orBasalt Monolithto ramp for your combo turn, and it is a creature to sacrifice.

Goldfished twice against Yisan, the Wanderer Bard today and managed to outrace him on turn 4 both games, with the modifications I listed you sonnet666. I would suggest you testing with those suggestions as they help make the deck faster by a lot, and this deck I really enjoy to play it now, your list is a blast!

Ok, a couple things:

• Soldevi Adnate can't sacrifice mana rocks, only black or artifact creatures. To sacrifice my mana rocks I'd need Priest of Yawgmoth. I thought about including them, but since my ramp is spilt between creatures and non-creatures, most mana rocks have low CMCs, and every creature that survives to 8 mana is an extra tutor for Razaketh, I felt they weren't worth it.

• Infernal Darkness doesn't cut the mana produced by lands. It just changes the color. I thought hosing everyone might be worth slowing down a little, and you can just sacrifice it the turn you want to go off. I'll probably cut Contamination, it was in there from when tutoring Bloodghast seemed like a good idea.

I'll look into those other edits.