I stayed fairly light on card draw, instead favoring to generate card advantage by replaying cheap cantripping permanents with Muldrotha. In addition, the card draw engines I did include are very powerful, and can be easily found using our tutors. Meanwhile, the tutors are pretty much all permanent based and can find a wide range of targets, allowing me to easily find what I need in any situation.
Buried Alive - One of the most powerful tutor effects for graveyard-based decks. In this deck especially, you can get a wide variety of things, either a set of value creatures, a set of reanimation targets, or anything in between. One package I like is Deadeye Navigator, Phyrexian Delver, and any creature whose etb effect you want to abuse. You can reanimate Delver with a reanimation spell, getting back Deadeye, then flicker the Delver to get back the other creature.
Diabolic Intent - A poor man's Demonic Tutor. Sometimes sacrificing a creature to it can even be an upside though, with Journey to Eternity
and World Shaper both in the deck. Either way, we pretty much always have some random value creature around to sacrifice to it.
Entomb - This card can do some pretty nutty thing and enable some incredibly broken starts. Opening T1 Entomb into T2 reanimation spell is one of the most powerful things you can do. It can be found off of Spellseeker, instant speed helps avoid telegraphing your plays, and it can find any permanent to replay with Muldrotha, or even a non-permanent to buyback another way.
Fauna Shaman - Much like Diabolic Intent, this is a powerful poor man's version of another ridiculous card. This one makes a decent impression of Survival of the Fittest. It's a lot slower, but the things it can do are just as ridiculous. You can turn your useless reanimation targets in hand into ramp to get off your feet, then later tutor up reanimation for them. I'm almost tempted to put this in the next section with the other ridiculous one-card value engines, but I'm not sure it quite makes it there.
Fierce Empath - This finds any of our reanimation targets, albeit to hand, but it's not like they're bad when played from hand, just more expensive.
Kiora, Master of the Depths - As I keep mentioning, Kiora is only in the deck to -2 over and over again, helping us hit our land drops while filling our hand with value creatures, and our graveyard with random stuff.
Mystic Remora - One of the few actual draw engines in the deck, it's only in the deck because of its incredibly high efficiency. Paying 1 mana for 1 or 2 cards is very powerful, especially when you can just replay it from the graveyard with Muldrotha once its cumulative upkeep becomes too high.
Neoform - Much like its much more broken ancestor Birthing Pod, this can accomplish some incredibly powerful things. Pretty much any opener with this and a cheap creature lets you ramp out Muldrotha early, and later in the game it can do much more powerful things, upgrading expensive etb-creatures into ones with powerful static abilities.
Sidisi, Undead Vizier - Diabolic Intent on a stick, it's a little more expensive, but can be recurred by Muldrotha or our reanimation spells, tutored by creature tutored, etc.
Skullclamp - Another of our draw engines, cashing in a value creature for 2 cards is pretty ridiculous, especially when it costs only 1 mana. We can also find this with our Trinket Mage.
Spellseeker - This card is incredibly powerful, finding removal, counters, or another tutor.
Sphinx of Uthuun - Fact or Fiction on a stick seems really strong, especially since we can reanimate it, flicker it, etc. Fills your hand and your graveyard very quickly.
Trinket Mage - In my opinion, this card is one of the most powerful restricted tutor effects in any Muldrotha deck. If you are on a budget, this finds powerful value engines like Nihil Spellbomb, and if you are running a more expensive build, you can find your Lion's Eye Diamond or Mana Crypt to play out Muldrotha really early.
Vivien, Champion of the Wilds - Most of the time this will be a 3-cost Divination that can be replayed from the graveyard. It can help you dig for ramp creatures in the early game, and later on dig for bombs. Its static ability cannot be underestimated either: flashing in Muldrotha or another threat on your opponent's end step is incredibly powerful.