Crawling Graveyard

I love a good self-mill deck. I've built several myself, they are quite fun to play. Here are just some general observations.

The top card to look at is Grist, the Hunger Tide, which does whatever you need it to do in a deck like this, and has cheap reprints.

Devourer Memory is a good idea, but is simply too slow (doesn't trigger per milled card), and eats mana for his own mill ability (3 per turn is a lot for 1 mill), so he should be cut.

Rumblweed is a game ender, but works best with fetch lands on top of self-mill. So I'd advise cutting Archway Commons (which I would anyway) in favor of any of the cheap fetch lands like Evolving Wilds to help pump up the dead land count. I think running 1 copy of Rumbleweed probably fits in this build, as you will only topdeck it (if you see it at all), or necro it, in either case with a full grave (hoping that opponent doesn't pull any shenanigans).

Molderhulk is fun, but the dead land isn't worth running the better versions of it instead, namely Ghoultree or Huskburster Swarm. Both are cheaper, stronger, and easier to cast color wise.

Sage of Mysteries has 10 targets to get mills with. In an average match, the most you'll get on that is mill 4 with a 0/2 that doesn't otherwise help you. It is basically an imperative to run the best critter mill in the game, Stitcher's Supplier. You're guaranteed a mill 3 on the enter, and will probably catch the second mill 3 with a chump block. Supplier is the best turn 1 drop you can have in a deck like this, hands down.

Vilespawn Spider is a bit slow, but does help mill with a potential win con on the back end. I'd personally rather run Cruel Somnophage // Can't Wake Up, Urborg Lhurgoyf, or Mire Triton, all of which are either faster, stronger, easier to cast, or all of the above.