Cool idea!

Hey, very good List. Maybe you should take Lotus Petal and Kaya's Ghostform in your deck too. Look in my decklist, with this 2 cards you have a lot of combo value. Regards

Kaya's Ghostform can't enchant Lotus Petal. Maybe you are thinking of another card Venoctus?

Bretagard Stronghold, Cryptic Caves, Encroaching Wastes, Blast Zone there are a ton of lands you can sac for value (and not that expensive of most).

Snake Basket is a lot of chump blockers but not thematic. Any of the Goad enchantments.

Oh never mind you just meant to combo with Muldrotha. I'm slow today, sorry.

Soul of the Harvest, Fertilid, Mulldrifter and Shriekmaw are good budget elementals.
Wolfbriar Elemental is a nice mana sink in the late game.
Consider adding backgrounds like Master Chef or Scion of Halaster.
You are running Joint Exploration. Consider similar cards like Explore or Growth Spiral. They can let your deck gain some early velocity.
If you play multiple elementals with evoke then a card like Village Rites becomes useful because you can cast it in response to the evoke trigger and draw 2. Card like Evolutionary Leap could also be used in response to evoke trigger to draw a fresh elemental
Zendikar's Roil can let you go wide with elementals.
Tatyova, Steward of Tides makes your lands into 3/3/ elementals
Kenrith's Transformation is a great removal spell that replaces itself and can be recurred.
Tezzeret's Gambit draws 2 cards and proliferates.
Nissa, Voice of Zendikar puts counters on each creature for just 3 mana

Cards I would replace:
- cards with kicker and Vine Gecko (they are generally worse cards than regular budget ramp spells like Rampant Growth or Cultivate)
- 6 forests because you have low mana curve (I would cut the land count to something like 36 lands, but you could also swap them for dual lands with basic land types from Kaldheim - Woodland Chasm, Dominaria United - Haunted Mire, Temple cycle - Temple of Malady or bounce lands - Golgari Rot Farm
- Titania, Protector of Argoth because there is only one card -> Harrow that can proc her ability to make elementals
I would also cut some of the elementals that don't have any useful abilties like Jaddi Lifestrider, Healer of the Glade, Glade Watcher, Floodhound, Offalsnout, Smolder Initiate and Slitherwisp.

Hope you find some of the suggestions helpful.

Love playing my muldrotha deck. Super-awesome budget add with a ton of value Spore Frog.

Hey, you've moved on from snow :) Nice version on budget, interesting strategy of proliferate. Unique combination of Muldrotha with Elementals and proliferate.

• Command Tower, Exotic Orchard, Path of Ancestry

Consider less basic Forests? Get more green sources from budget dual lands to help color fixing? Command Tower is a staple land in Commander for multicolored decks. Exotic Orchard in multiplayer Commander will rarely not make the color of mana you need. Path of Ancestry is a Tri land that also provides repeatable scry when used to cast an Elemental.

• Yavimaya Coast, Llanowar Wastes, Underground River

The Pain lands ETB untapped and in my opinion they're among the best budget dual lands in Commander. Wastes and River have just been reprinted in the latest Standard set Brother's War.

• Sunken Hollow, Necroblossom Snarl, Necroblossom Snarl, Choked Estuary

Even cutting some basic Forests for dual lands you'll still have many basic lands therefore consider some dual lands that care about basic lands? The Snarls care about basic Forest in hand and you'll have many of them.

• Sol Ring, Arcane Signet

These are staple budget mana rocks in Commander. Sol Ring can be really helpful to cast Muldrotha.

• Cavalier of Night, Cavalier of Gales

Improving color fixing from lands can also help to cast the five drop budget Cavalier Elementals who have nice ETB trigger and die trigger, that's good with Muldrotha. Cavalier of Night is also a sac source to sac a creature you control to cast it again with Muldrotha.

• Eternal Witness, Neoform, Jarad's Orders

These are excellent budget cards with Muldrotha and have synergy. The creature you get with Neoform ETB with a counter, ready for proliferate. Jarad's Orders can tutor for Witness and another creature.

Good luck with your deck.