Hello, this is my Gitrog list, a combo focused duel commander.
Starting with the basics, the combo, phase 1. It is a 3 piece combo, first piece you should have is your commander, the second piece is a discard source and the third is a dredge card.
With these 3 pieces you should be able to begin your dredge machine, since there are 44 lands vs 56 cards, a 3 card dredge should get you going, at least for a while, because whenever you dredge a land you may discard the dredge card and dredge again, until you hit the best dredge card, Dakmor Salvage. With it, you can dredge and draw the whole deck, until you hit Ulamog or Emrakul, whenever they go to your graveyard you shufle all your cards back and keep going until you draw all cards from your deck, keeping only lands on your grimoire.
After that, you will cast a Lotus Petal or use a Dark Ritual, discard Ulamog or Kozilek, then discard Dakmor to begin the draws again, draw these two back, and repeat the whole thing infinite times for infinite mana. You can do infinite casts of the whole deck, it's easy to win with it that way, when there are things like Beast Within, Abrupt Decay, Dimir Machinations, Shred Memory and Raven's Crime.
The whole deck is focused on getting the combo asap, preferably on the 4th turn. You have 7 discard sources and 6 dredge sources, with at least dredge 3, besides that you have 13 tutors that can get at least one discard or dredge piece and 1 that can get only the Dakmor Salvage. That puts the deck in a 20% chance of getting each piece of the combo, which means 1/5 cards will be a combo piece or a tutor for a combo piece, since our goal is the fourth turn, this means almost certain to posses the necessary cards with the 10 cards we draw from 1st turn until the 4th.
In order to achieve that 4th turn, I used most independent ramps with CMC 1-3, I don't like to rely upon having a forest or something like that. The ideal play would be tapped land or 1 mana ramps on the first turn, a tutor on the second, case you can't do something to control your opponent or a CMC 2 ramp. On the third a discard source, case you can't do a tutor. on the fourth you should have a dredge card, on your hand or graveyard, and a discard source in play, now we are only missing Gitrog, since you should have ramped at least once, you should be able to cast it. It's most likelly that you will do all this by the 5th turn but with luck you can do it in the 3rd~4th.
I used some control and high sinergy cards in this deck, they are not essencial, but the spine of the deck is the Ulamog and the Emrakul, the tutors, dredge and discard sources, and of course the commander, besides that is all up to you to adapt the list to your liking, hope you guys enjoy it and if possible give it a like =)
Thank you very much for reading!
PS: Sorry if I messed the text up, english is not my primary language!