Theme: My graveyard is just an extension of the cards in my hand.
Let's go through my thought process while making this deck.
Muldrotha gives you the ability to play one of each permanent type from the graveyard each turn, I decided to go with the obvious build and mill a ton of my own cards so that I would have more options for what to do on each of my turns. But since it's a self mill deck, and I can only play permanents from the graveyard, I decided to barely use any instants or sorceries at all. I focused on permanents that can accomplish similar things. The problem with this is that most of these will only be able to do things on my own turns. I'm not sure yet how well it will work.
Being able to cast one of each permanent type from the graveyard each turn means that if I want to fully utilize this ability, I would need lots of mana available, or lots of very low cost permanents of different types. I kind of went both ways for this.
So it's a mill deck that isn't set up to play instants and sorceries from the graveyard, that meant that a lot of green ramp staples were not great in the deck. So instead I focused on using a lot of permanent types of ramp that sacrifice itself, so I can reuse it from the graveyard for even more ramp.
I still kept a few instants and sorceries, but only because they synergize with the graveyard theme really well, and I figure if I can start the game with one or two of them in hand it can make a significant impact on the beginning of the game. If I'm lucky enough to draw one later instead of milling it, that's a bonus.
With the thought that I would have access to the graveyard as an extension of my hand, I know there's a lot of lands that can be immediately sacrificed for bringing out a basic land from the library. I figured that once any of these free sacrifice lands are in the graveyard and Muldrotha is on the board, I will be able to use them every turn and never miss a land drop. So I packed the deck with free immediate sacrifice lands, and a bunch of basics that can be pulled out of the library. Also I don't enjoy spending high prices on the good dual lands, so lots of basics is good for me.
So following that line of thought, being able to play and freely sacrifice a land every turn, that means that anything that has a landfall trigger will be able to get two triggers every turn. So I found a bunch of landfall cards that will hopefully be able to get maximum value every turn. After putting a bunch of significant landfall cards in the deck, it felt like the right idea to lean more heavily into the landfall and add in a bunch of things that can cause more and more landfall triggers to really maximize the value.
I know that inevitably I will end up with basic lands in hand and in the graveyard. I figure I will use those when I don't have any good landfall triggers to activate or just attempt to discard the basics and eventually have world shaper bring them all back at once while having Scute Swarm in play.
In trying to maximize the ability of the commander, I also sprinkled in a bunch of planeswalkers because they're a permanent type too. In my play group I think we've only ever seen a planeswalker ultimate like one or twice. Maybe with a bunch of different targets I'll be able to get one to ult finally.
There's a really convoluted win combo with having Curse of Unbinding on myself, and Reito Sentinel on the board. First cast Old Stick Fingers with a high enough X cost to bin all of the remaining creatures in the library, then waiting for my next turn. At my upkeep with the Curse of Unbinding trigger on the stack, using Reito Sentinel to put Thassa's Oracle from the graveyard to the bottom of the library. Curse of unbinding would mill the rest of the library to empty, and Thassa's ETB trigger would win the game.
It also works with Unbinding and Jace on the board instead of Reito Sentinel, and using Old Stickfingers to bin the rest of the creatures. Either way, if a player is observant, then they will probably see the Curse of Unbinding milling the rest of the library coming and have a chance to stop it.
Changes to consider if the deck doesn't end up playing well:
First off is if not having many instants makes the deck too passive and lacks the ability to respond effectively, I would add Lier, Disciple of the Drowned and add in high value instant and sorcery cards.
It doesn't really replace instants, but one option to replace sorcery cards is to put more creature in the deck with Evoke abilities. That way the creature dies immediately so that the effect can be reused from the graveyard. Foundation Breaker as an evoke for repeatable enchantment / artifact removal. Mournehelk for hating an individual player. Night Incarnate for low to the ground board wipe.
Also, I intentionally didn't add any board wipes, but if I change my mind on that, the obvious targets are permanent based board wipes, like creatures that ETB with a board wipe or artifacts like Nevinyrral's Disk.
I think it might be a good idea to slot in some free sacrifice outlets, specifically to be able to dodge exile effects on important cards. Claws of Gix isn't a free sac, but it seems like a good option for any non creature permanents, and there's a lot of possible options for free sac outlets for creatures.
Another thing that could make a nice boost for the deck is to try to spread out the permanent types more by having more artifact creatures or enchantment creatures so that up to three creatures can be cast from the graveyard each turn.
This is my first time making a self mill deck, so I added Jace and Thassa's Oracle for potential deck out wins, but then again I don't know if I leaned heavily enough into the self mill to actually deck out. If not, I will probably remove those from the deck and slot in some other cards that synergize with the rest of the deck.
I found a couple of extra cards that give discounts to spells being cast from the graveyard. Will probably try to fit them into the deck.
It might be worthwhile to slot in Vorinclex and some planeswalkers with high impact emblem based ultimates.
Side note: Oh my god, I just realized that Scute Swarm mutate combo could be amazing in this deck. Get Brokkos, Apex of Forever and Scute Swarm into hand or graveyard, cast Scute Swarm, then if both were in the yard use Brokkos innate ability to mutate from the yard onto scute, trigger a ton of landfall all at once, have a massive army of 6/6 trample Scutes. Concordant Crossroads haste would turn that into a one hit kill.
