Self-mill and reanimation are directions to consider expanding. However, before you think about them consider first focusing on more ramp (0-3 CMC)?

Muldrotha is 6 mana and you have very few lower mana cost ramp spells. Scions aren't really reliable ramp since they only give you a burst of colorless mana after being saced. Consider more ramp that you can use more than one turn? More ramp like this can help gameplay, make it easier to cast your higher mana cost spells especially Muldrotha and give you more mana to cast different spells from your graveyard when you control Muldrotha. Consider at least 12 ramp sources?

• Birds of Paradise
• Bloom Tender
• Lotus Petal
• Arcane Signet
• Fellwar Stone
• Sakura-Tribe Elder
• Harrow
• Springbloom Druid
• Farseek gets Triome
• Nature's Lore gets Triome

Carpet of Flowers is powerful mana generation in multiplayer Commander.

Another direction to consider is to play more effects that let you play more than one land a turn. This makes Life from the Loam more powerful since you're filling your hand with lands.

• Exploration
• Burgeoning
• Dryad of the Ilysian Grove
• Loot, Exuberant Explorer
• Azusa, Lost but Seeking

Eternal Witness is really good with Muldrotha and self-mill since it gives you access to any card in your graveyard, a nonpermanent spell such as Diabolic Intent that you can't cast with Muldrotha.

Cut Demon of Loathing in Thraximundar? Cut a 7 drop for a 3 drop. Loathing is lackluster compared to the other 7 drops. It only makes one opponent sac a creature and only if it gets through.

Cut True Conviction in Tariel? Cut a 6 drop for a 3 drop. Conviction seems pretty difficult to cast with current manabase. It's mana cost is problematic when there's 21 lands that includes 16 basic lands that can't make white mana. You don't really need Conviction when you have Akroma's Memorial.

Hey, interesting deck.

Consider adding green? By adding green you get Glimpse of Nature, Noxious Revival, Elvish Spirit Guide. Glimpse and Revival go well together to keep casting Glimpse. Guide provides a green mana source without needing a land that can make green. Green also has Assault Formation, not needing an anthem effect to increase Kobolds power since only toughness matters. With 4x Glimpse you would only need 1x Formation as well as some kind of haste for all your creatures source such as Burst of Speed that you cast after casting all your Kobolds for the turn. With 4x Glimpse, 1x Grapeshot is all you need.

Stomping Ground, Karplusan Forest, Copperline Gorge can be dual lands that could replace Mountains? Lotus Petal and/or Wild Cantor, replacing some Mountains gives you a mana source of any color while also counting towards storm. The problems with Impact Tremors and Purphoros, God of the Forge are they need to be on the battlefield before you start casting Kobolds. In theory Tremors/Purphoros seem good, but in gameplay they seem slow, too inconsistent hit or miss.

Consider this package for upgrades?

• 4x Glimpse of Nature
• 4x Elvish Spirit Guide
• 2x Noxious Revival
• 4x Lotus Petal or 4x Wild Cantor
• 1x Assault Formation
• 1x Burst of Speed
• 4x Stomping Ground or Karplusan Forest
• 4x Copperline Gorge

Good luck with your deck.

You're welcome and thanks for the upvote at my Lathril deck.

You could use card images from Gatherer and scale them down to the size you want with CSS. Add more properties to the style attribute for each image, width:223px;height:311px; these sizes will let you place three images before you need another row.

<div>
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" style="display:inline-block;width:223px;height:311px;">
</div>

When you start wanting more CSS properties then just one then using a class instead of a style attribute will allow you much less coding.

<style>
.imgline {display:inline-block;width:223px;height:311px;}
</style>

<div>
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" class="imgline">
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" class="imgline">
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" class="imgline">
</div>

This example is still using CSS, but the code is making it much more convenient to make changes or additions. You create one CSS class called imgline that's inside style tags; all the CSS properties you want to apply to each image are stored in this class, one place. Each image instead of a style gets a class attribute, class="imgline" or whatever you name the class. Any CSS properties you add to .imgline will be applied to every image that has class="imgline".

Hey, use inline CSS.

<div>
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" style="display:inline-block;">
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" style="display:inline-block;">
<img src="https://gatherer.wizards.com/Handlers/Image.ashx?type=card&multiverseid=673607" style="display:inline-block;">
</div>

Each image needs a CSS style with display:inline-block, that's the CSS property you apply to the image to make it form a line of images.