The reprinted cheap Cycle lands + Life from the loam is a very good draw engine once online. The draw trigger from cycling is the perfect for dredge on Life from the loam for grinding out great card advantage.
Main deck Surgical Extraction is always pretty ruthless. If Wrenn and Six goes ultimate, you can hit them several extra times. A couple Noxious Revival, or now Regrowth, would be worth running for that type of interaction by its self.
It's really exciting for me to see the Loam engine getting a rebirth in Modern. I'm very much looking forward to seeing if a competitive deck based on it can emerge.
If you've considered what I have to offer already, feel free to disregard it... If not, I hope this helps with brainstorming. My suggestions will likely take the deck in a different direction than your current list, but as a long-time Legacy Lands player it's the direction I would personally go. A middleground between the following and what you have might be something akin to the old Legacy Aggro Loam lists relying on Tarmogoyf, Knight of the Reliquary, and so on to present a strong offense in combat. If you're willing to explore Naya instead of Jund, Hall of Heliod's Generosity can add resiliency given the enchantment-based wincons that synergize with the engine, and can make dredge decisions less impactful.
Ramunap Excavator and Tireless Tracker are a couple of things you should consider off the bat as both are very powerful and synergize with the Loam engine well.
The primary strength of the Loam engine in Legacy has always been not only breaking card advantage parity but also, perhaps more importantly, land drop parity. Having access to multiple land drops is what makes Ghost Quarter really shine, and allows you to have the resources to really abuse the engine to cast multiple spells or cycle multiple lands per turn or even dredge loam multiple times. Explore, Rites of Flourishing, Azusa, Lost but Seeking, Mina and Denn, Wildborn, Oracle of Mul Daya, and Wayward Swordtooth would all be on my list for testing in a deck trying to really take advantage of the loam engine. Also, Boseiju, Who Shelters All, Bojuka Bog, and other such utility lands can expand your options in a deck that expects to see a lot of lands. Admittedly, breaking land drop parity is much more powerful in Legacy given the lands legal there, but I think the potential advantages are worth investigating in Modern.
What Im looking to do with this version of the Loam deck is really exploit the 1cmc Cycle Lands for draw and the disruption lands, primarily, Ghost Quarter and to a lesser extent Blast Zone combined with Surgical Extraction to play as unfairly as possible. The idea being to slow play down in the same manner that Control does. Grind, grind, grind. If someone gets hit with Surgical Extraction once, its pretty bad for them. Twice, via Regrowth, can be crippling. Regrowth is a VERY direct path to reuse cards. It being reprinted into Modern is fertile ground for exploitation. Dreadhorde Arcanist would be something of a Snapcaster Mage for this deck.
If your goal is prisony/grindy, look into some artifacts to bolster that gameplan, such as Damping Sphere, Ensnaring Bridge, Defense Grid or even Trinisphere, Pithing Needle, or Thorn of Amethyst as sideboard considerations. Bridge would lend itself to focusing on non-combat wincons like Vortex or retracing burn with Wrenn and Six's emblem.
4 Wrenn and Six
4 Life from the Loam
Draw
4 Faithless Looting
4 Dark Confidant
Disruption
4 Assassin's Trophy
4 Raven's Crime
4 Surgical Extraction
4 Ayula's Influence
Soft Locks
3 Blast Zone
3 Ghost Quarter
Mana Package
4 Bloodstained Mire
4 Wooded Foothills
2 Overgrown Tomb
2 Stomping Ground
4 Tranquil Thicket
2 Barren Moor
The reprinted cheap Cycle lands + Life from the loam is a very good draw engine once online. The draw trigger from cycling is the perfect for dredge on Life from the loam for grinding out great card advantage.
Ghost Quarter and Blast Zone apply a steady and repeatable board pressure. Against many decks Ghost Quarter quickly becomes a Strip mine.
Main deck Surgical Extraction is always pretty ruthless. If Wrenn and Six goes ultimate, you can hit them several extra times. A couple Noxious Revival, or now Regrowth, would be worth running for that type of interaction by its self.
Surgical Extraction --> Noxious Revival + Tranquil Thicket --> Surgical Extraction
Good bye threats or wincons!
If you've considered what I have to offer already, feel free to disregard it... If not, I hope this helps with brainstorming. My suggestions will likely take the deck in a different direction than your current list, but as a long-time Legacy Lands player it's the direction I would personally go. A middleground between the following and what you have might be something akin to the old Legacy Aggro Loam lists relying on Tarmogoyf, Knight of the Reliquary, and so on to present a strong offense in combat. If you're willing to explore Naya instead of Jund, Hall of Heliod's Generosity can add resiliency given the enchantment-based wincons that synergize with the engine, and can make dredge decisions less impactful.
Ramunap Excavator and Tireless Tracker are a couple of things you should consider off the bat as both are very powerful and synergize with the Loam engine well.
The primary strength of the Loam engine in Legacy has always been not only breaking card advantage parity but also, perhaps more importantly, land drop parity. Having access to multiple land drops is what makes Ghost Quarter really shine, and allows you to have the resources to really abuse the engine to cast multiple spells or cycle multiple lands per turn or even dredge loam multiple times. Explore, Rites of Flourishing, Azusa, Lost but Seeking, Mina and Denn, Wildborn, Oracle of Mul Daya, and Wayward Swordtooth would all be on my list for testing in a deck trying to really take advantage of the loam engine. Also, Boseiju, Who Shelters All, Bojuka Bog, and other such utility lands can expand your options in a deck that expects to see a lot of lands. Admittedly, breaking land drop parity is much more powerful in Legacy given the lands legal there, but I think the potential advantages are worth investigating in Modern.
Seismic Assault, Molten Vortex, and Living Twister are all worth considering to bolster your wincon options alongside Ayula's Influence as well as act as durable removal.
Other Dredge cards such as Shenanigans and Darkblast may also be valuable, as well as Ancient Grudge, and cards with Retrace such as Flame Jab, Worm Harvest, and depending on your build, Throes of Chaos.
Legacy - WRG Lands, WR Shortcake, RR Burn, UBRG Delver
What Im looking to do with this version of the Loam deck is really exploit the 1cmc Cycle Lands for draw and the disruption lands, primarily, Ghost Quarter and to a lesser extent Blast Zone combined with Surgical Extraction to play as unfairly as possible. The idea being to slow play down in the same manner that Control does. Grind, grind, grind. If someone gets hit with Surgical Extraction once, its pretty bad for them. Twice, via Regrowth, can be crippling. Regrowth is a VERY direct path to reuse cards. It being reprinted into Modern is fertile ground for exploitation. Dreadhorde Arcanist would be something of a Snapcaster Mage for this deck.
Likely Better:
4 Wrenn and Six
4 Life from the Loam
Draw
4 Faithless Looting
3 Regrowth
Disruption
4 Assassin's Trophy
4 Raven's Crime
4 Surgical Extraction
3 Zombie Infestation
2 Molten Vortex
Soft Locks
4 Ghost Quarter
2 Blast Zone
Mana Package
4 Bloodstained Mire
4 Wooded Foothills
2 Overgrown Tomb
2 Stomping Ground
4 Tranquil Thicket
2 Barren Moor
If your goal is prisony/grindy, look into some artifacts to bolster that gameplan, such as Damping Sphere, Ensnaring Bridge, Defense Grid or even Trinisphere, Pithing Needle, or Thorn of Amethyst as sideboard considerations. Bridge would lend itself to focusing on non-combat wincons like Vortex or retracing burn with Wrenn and Six's emblem.
Legacy - WRG Lands, WR Shortcake, RR Burn, UBRG Delver
lol SaffonOlive did it better