I have rethought how to build this deck. My first time around, I did not realize that I wanted artifact creatures that I could cast with Muldrotha as a creature or as an artifact. Same deal for Enchantment Creatures. Muldrotha and Theros go really well together. Here is a list that works very well. I may make a substitution or two, yet, right now, I am very pleased with the results of solitaire testing.
I want to cast Muldrotha as soon as possible.
And I want to feed the graveyard a lot.
With Erebos, I can draw extra cards quickly. I don't even need Erebos as a creature in this deck, that's a bonus.
I can sacrifice something bigger, or I can sacrifice Strangleroot Geist and it comes right back.
Uncage the Menagerie draws me X cards at X CMC (2 for 2, 3 for 3, and so on). There is nothing wrong with netting only two two-drops, if they are the right draws at a specific point in the game.
Kefnet can attack with 7 OR MORE cards in hand, and not exactly 7. I can discard and then cast those discarded cards with Muldrotha....sweet, at least in Solitaire.
I can sacrifice Elvish Visionary and cast him again for the ETB draw.
Here I have lined up cards that I am ready to drop in my graveyard when my hand ha gotten too big at the end of the turn.
The geist comes back... nice.
This deck is intricate, and full of interesting combos. I have barely scratched the surface of how it can be played.