RG Assault Loam (Modern)

Been tinkering with this archetype for a while, it's definitely one of my favourites. I mostly play on FNM-grade events, and have somewhat of a positive score with this strategy.

//THE DECK

The core of the deck is the engine Seismic Assault + Life from the Loam. Basically it's a repeatable source of damage with which you can either finish your opponent or stabilize the board. The other threats either help you get the engine running or synergize with it:
Countryside Crusher by itself can be a very real game-ender, all the while grows even faster if you have an Assault out, and helps you dig for additional threats/Life from the Loam on your upkeep.
Tarmogoyf gets bigger than expected due to the number of Enchantments and self-mill effects.
Raging Ravine becomes a bigger threat when you can recur it freely with Loam.
Crawling Sensation helps you dig for Loam while providing numerous blockers (and eventually, attackers).
Ghost Quarter/Tectonic Edge become very real threats to your opponent's manabase, with great recursion.

Now to address the elephant in the room: being a graveyard-based deck in Modern can be pretty rough, but it's not impossíble. Most of the commonplace graveyard removal are either directed at the Dredge deck (Grafdigger's Cage doesn't affect Life from the Loam, and it's popular against Collected Company as well) or one-shot effects such as Relic of Progenitus, Nihil Spellbomb or Tormod's Crypt. Of course it sucks, but it's very possible to play around these and bait your opponent into wasting their graveyard removal before fully commiting to the engine. Rest in Peace, of course, is a beating - which is why it's imperative you sideboard accordingly (cut Goyfs for Revelries) and mulligan aggressively. Even with RIP out, it's possible to slam Assault and naturally draw lands to kill your opponent's threats, and finish him with a 2/2 Ooze. Yes. It happens.

//THE SIDEBOARD

The field I play in is very straightforward - there are a couple of linear/combo decks such as Ad Nauseam, Infect, Griselshoal and whatnot, with sprinkles of blue-black or blue-white based hard control and a few dedicated tribal aggro decks. My current sideboard takes into consideration that I'll need to either stall the game to get the engine online or to answer graveyard hate or side-in additional win conditions that don't get as affected by graveyard hate.

There are three main clusters of sideboard cards, the first one being specific hosers: Grafdigger's Cage and Sudden Shock are there to properly address Dredge/Griselshoal/Company/Snapcaster-based decks and Infect respectively.

The second one, the general answers: Destructive Revelry is there to deal with troublesome Leylines/RIPs as usual, while Anger of the Gods helps against many aggro matchups. Feed the Clan can be an additional tool to outrace aggressive strategies or a very necessary addition against Burn. Lastly, Fog is a very generalistic answer to Griselshoal, Infect, Bogles and other aggressive strategies alike. It's mostly used as a "time walk".

Finally, the third cluster holds the grindy-matchup cards: Thrun, the Last Troll, Thragtusk and Worm Harvest. Worm Harvest won't ever come in if the opponent is playing White (since it's awful against Rest in Peace), while both Tusk and Thrun are at their peak against blue-based control with targeted removal. Tusk isn't as impressive as Thrun, but imposes a fast clock while stabilizing the life total and requiring 2+ answers due to the token, so that's straight up value. Keep in mind the maindeck Haunted Fengraf to properly outgrind your opponents.

//CARD COMMENTS

Here I'll start to place a few comments on old cards that I used to play in this deck, as well as recent cards that have been catching my eye.

Molten Vortex
Holy crap, was I happy when this was spoiled. It's basically Seismic Assaults #5~8 with the amazing upside of constantly being played before your opponent has countermagic up. Also makes Abrupt Decay increasingly worse (now you have a crapton more targets than before), and makes Pithing Needle only 50% as effective as before. Paying mana for the activation can be a bother, but it IS a very strong card that can't be underestimated. Helps immensely against Burn and aggro, is really good against control and used to be one of the better cards against Splinter Twin.

Countryside Crusher
Really easy to underestimate - but this guy hits hard. If playing against red, hedge against Lightning Bolt by playing it on 4 with a fetchland ready to crack, and that's it. The upkeep trigger can have mad variance - but usually getting it to 5/5 or 6/6 is enough. Keep in mind the math with Seismic Assault: each Assault activation means 2 damage and +1 Crusher damage, which can lead to ridiculous swings if your opponent had no blockers. By the way, with Assault you can always clear the path and get some profit out of the big guy.

Crawling Sensation
This card can be a real powerhouse in grindy matchups - mostly because if fills several different roles at a reasonable cost and synergizes really well with the rest of the deck. By itself, this helps you dig for Life from the Loam, while nets you a few chump blockers to gain more time. With 26 lands it's crazy easy to trigger this on your turn, and considering the amount of lands that sacrifice themselves, it's somewhat easy to trigger this on your opponent's turn as well. Dredge also makes the token trigger very easy to achieve. The synergy with Seismic Assault is crazy - you get to completely blank some attacks by killing creatures and chumping, then start amassing an impressive board presence by merely throwing a land at a time. It's crazy good, fulfills pretty much what Young Pyromancer used to do in older versions.

Young Pyromancer
Used to be an all-star because my old lists used to run Flame Jab (and Raven's Crime if I splashed black). Had great synergy with more spell-based configurations, in which Magmatic Insight/Tormenting Voice could be amazing as well. Also, sweet synergy with Smallpox (since you get the token before having to sac a creature). The Young Pyromancer deck is still very viable - but it's a whole other path. It focuses a lot more on Retrace spells, and in that case Burning Vengeance becomes a tad better than Seismic Assault. The twist, though, is that is suffers even more to graveyard hate.

Noose Constrictor
Tested a little bit, showed promise. It's a cool way to fuel the graveyard, grow Crusher a bit faster without an Assault/Vortex and can even block flying creatures, which is a soft spot for this deck. Wasn't sold on it, though - but I wouldn't dismiss it completely, since it's a way to convert Life from the Loam lands into damage under Leyline of Sanctity (even if a bit iffy).

Eternal Witness
For the longest time ran it as a 1-of to help in grindy matchups. Thing is - it didn't help as much. Today, with Haunted Fengraf, it might be more appealing but still comes to me as excessively slow. It's not a win condition on it's own, and does very little to improve the board state. Mostly, I found that simply having additional threats and redundancy was more effective than taking a turn off to replay a threat that had already been answered. But it's not out of the table, by any means.

Magmatic Insight
Seemed great, instantly put 4 in the deck. Again, in Young Pyromancer builds, it really performed nicely - but didn't pull it's own weight. Might be fine as a 2-of or something, but definitely not a fan. The "discard a land" clause sounds like a great deal, but wasn't enough. Ran it on a 28-land build, wouldn't run it with my current 26.

Vessel of Nascency
Recently been testing it - with mostly positive results. Used to run Commune with the Gods - on one hand, powerful effect that actively helped me win games and get the engine running; on the other, 2 mana at sorcery speed while NOT advancing the board state isn't exactly where I want to be against Spell Snare, Remand and friends. Vessel of Nascency seemed to combine a couple of things I really liked - mostly the same effect (with the upside of getting Land or Artifact post-side), even if seeing 1 card short, didn't have to be done at sorcery speed, and was another 1 CMC spell. Given how easy it was for the deck to get either R/G on turns 1 and 2, I thought it could be worth a shot, and here it is. I really like how it can just sit there for a while, and if I feel like I need some additional threat I can just pop it whenever. Also - bonus - it really helps the Tarmogoyf grow by a lot, since it by itself adds Enchantment to the graveyard, and I'll mill at least 3 more cards.

Haunted Fengraf
Used to be Ghost Quarter #3, friend of mine convinced me to try it. It has been... iffy, but important. In some matchups the advantage of being able to recur creatures is very real, and it's crazy easy to recur the land because of Life from the Loam. It's not costing me much in terms of mana efficiency or Ghost Quarter slots, and the upside is pretty great. Also really helps the "grindy matchup plan" postboard, with Thrun/Tusk and whatnot.

//ADDITIONAL COLORS

There are a lot of options for the Seismic Assault + Life from the Loam archetype. I personally prefer R/G because it allows me to keep the greediest hands, achieve the craziest board states and have the lowest chance of getting mana screwed. It's not easy to get RRR on turn 3, and this has a very real cost on your gameplan. Most of the splash options tend to favor Molten Vortex over Seismic Assault because of that, worth noting.

Other styles of Red/Green Assault could focus on a Blood Moon theme - or even ramp! There are also a couple of RG Ponza Assault builds out there - which combine the heavy Land Destruction elements with utility lands, Blood Moon and Seismic Assault as a finisher. Also, ramp strategies could benefit from Seismic Assault to start the engine by turn 2 and give the opponent a very small window of opportunity to get back into the game. Lastly, there are the 45-land Countryside Crusher decks.

On a very broad sense, the most popular splash is Black. Playing Jund offers a lot of advantages such as better removal (Terminate, Abrupt Decay), added disruption (Inquisition of Kozilek, Thoughtseize, Raven's Crime) and very powerful effects (Kolaghan's Command, Dark Confidant, Liliana of the Veil). That said, it's very viable to turn it into a Young Pyromancer deck with a lot of spells and disruption, with the Life from the Loam engines being the icing in the cake. Getting access to Ghost Quarter recursion and consistent Liliana of the Veil discards can be really spicy, and people tend to like it a lot.

There's also Blue - which brings a ton of useful disruption and cool effects. Izzet Charm and Remand come out as the better reasons to play Blue, with Deprive, Trade Routes and Gifts Ungiven soon behind. Temur Assault tends to work a bit more as a control deck with the engine acting as a wincon - while adding the Ghost Quarter as an additional disruptive element. There are some amazing shells to build upon, from hard disruption to very synergistic combos. The main focus is usually on having efficient game plans, with a lot of possibilities and unexpected turns. That aside, there's also the Treasure Hunt decks that can use Seismic Assault as an alternative to Zombie Infestation or Conflagrate.

Finally, the White splash gets one of the better beaters - Knight of the Reliquary. The pros are great - you get to play big, efficient beaters while stiff having access to the Seismic Assault engine to both acquire reach and clear the path! Also, Path to Exile is an amazing addition to the deck, since it makes some turns that would be spent on killing a big opposing creature into "Path your guy, 6 to your face". These builds tend to be more centered around the aggressive side - actually resembling Big Zoo with the Assault for finish and value. On a midrange base, though, Restoration Angel and efficient blockers can keep attackers at bay while you assemble the engine - while less popular, it's still out there.

//FINAL CONSIDERATIONS

Hope you enjoyed this list, and in case you're interested in what you can do with this kind of shell, feel free to ask me for any kind of advice ^^
This deck is very fun to play, and leads to impressive board states and interactive matches. You get to choose from a large variety of strategies, and it doesn't actually fold to whatever piece of disruption - since it can always come back or just roll with another engine.