DedWards

That is more of a space problem than a cost problem. The only reason I included the two twigs was because the deck suffers without the turn one land ramp play. Thinking about it now, maybe I should replace the twigs with Renegade Map?

lol. It's less that they inspired me and more that they reminded me about it. I've been working on this since Korlash was printed (I have 4 alt art dated foils). Lashwrithe took the deck from "OK" to "Pretty Decent".

Because I'm building this on the side, with stuff I can easily get my hands on (kind of budget, despite having all full art swamps), I have not included Kalitas, Lili, nor the good discard like Inquisition because I just don't have them. Also makes this somewhat "fair" when I play against the newer players in the club. Sadly, Ponza has eaten up most of my MTG budget over the last two years.

Big Chandra has proven herself very useful as a 1 of in this deck (I own 3). The other two are being tested as they give, in theory, some strong advantages.

Although, Massacre Wurm is actually a good contender for Stronghold Discipline's spot. It's got a higher cmc, but it's a mini wrath that drains.

Assembling Tron would be slightly more reliable if you included a set of Expedition Map, which would make your X spells more reliable.
Bonfire of the Damned would also work well here.

Took me a while to check the prices. All the following should cost between $0.10 and $1.50 per card.

We have 2 pump options, with a few overlapping cards.

1) Agressive, low cost:
These are the cheapest (mana wise) creatures that get pumped via landfall with low cost landfall triggers.

The Creatures:
> Scythe Leopard: Lowest mana cost, but only gets +1/+1 from landfall.
> Plated Geopede: Best cost to effect ratio among the low mana landfall creatures.
> Makindi Sliderunner: Trample is this one's strongest effect.
> Snapping Gnarlid: Decent base stats for its cost.
> Vinelasher Kudzu: +1/+1 counters is what makes this good.
> Valakut Predator: Worse version of Plated Geopede, but +2/+2 is nothing to scoff at.
> Sylvan Advocate: While not a landfall creature, 2 for a 4/5 with vigilance is good.
> Undergrowth Champion: Ab upgrade to Vinelasher Kudzu.

The Landfall Triggers:
> Rampant Growth: Classic land ramp.
> Sakura-Tribe Elder: Rampant Growth on legs. Lets you ramp whenever you want.
> Evolving Wilds / Terramorphic Expanse: Cheap fetch lands that can trigger landfall twice in one turn.
> Firewild Borderpost / Gruul Turf: Bounces a land to hand, allowing you to replay it to get another trigger.

Utility:
> Retreat to Kazandu: Free +1/+1 counters for your creatures.
> Ground Swell / Swell of Growth: Landfall appropriate pump spells.
> Adventuring Gear: Additional +2/+2 per landfall on equipped creature.
> Skarrg, the Rage Pits: Poor man's Kessig Wolf Run. Trample is important.
> Teetering Peaks: Additional +2/+0 on top of a landfall trigger.

2) Big and Beefy:
Significantly slower than the aggro above, but packs a larger punch.

Creatures:
> Undergrowth Champion: The midrange idea can pull out more lands at once, making this a sizable threat for its cost.
> Embodiment of Fury / Embodiment of Insight: While these don't get bigger from landfall, they do allow you to go wide. Works well with Sylvan Advocate.
> Grove Rumbler: Arguably the best landfall creature at this cmc. The trample is very important.
> Baloth Woodcrasher: Grove Rumbler's big brother?
> Woodborn Behemoth: 5 for an 8/8 trampler (most of the time)
> Oran-Rief Hydra: +1/+1 counters is more powerful than temporary +1/+1, especially when doubled on half the lands entering.
You might want to include some of the smaller creatures, like Sylvan Advocate and Sakura-Tribe Elder, to act as blockers while you set up for the bigger creatures.

The Landfall Triggers:
While aggro above wants cheap search, you can use the same search here, and the following.
> Search for Tomorrow: Can suspend on turn 1, and puts the land in untapped. One of my personal favourite land search spells.
> Explosive Vegetation / Ranger's Path: Midrange can afford these multiple land search options.
> Nissa's Renewal: As this version is slightly slower, the 7 life gain is important.

Utility:
Mostly the same as for Aggro, but also consider:
> Pulse of Murasa: Returns any important creature to hand, or returns a fetch land, allowing for 2 more landfall triggers. The 6 life is also relevant.
> Zendikar's Roil: Extra blockers while ramping up your big creatures. Also an alternative win condition.

Ok, First thing I want to point out is that you seem to have two different landfall things going here:

1) Temporary pump:
Plated Geopede; Snapping Gnarlid; Baloth Woodcrasher; and Grove Rumbler, of which the first 2 are aggressive, while the latter two or more midrang-y.

2) Extra Value:
Rampaging Baloths is the only one in the deck in this category, but you did just mentioned Avenger of Zendikar, which is another.

I suggest choosing one mode or another, but not both. Once you've made your choice, I can give you my ideas, including what I consider to be more efficient landfall trigger / land search cards.

What type of budget are you on? Because I have a few ideas

What I mean is if you going to play blue, play blue. Blue has the strongest card advantage in draw spells and specialises in fetching artifacts, allowing you to get Liquimetal Coating more reliably. And then there's the controlling cards like counterspells and bounce cards. Boomerang comes to mind as it can be used on any permanent, including lands, giving you a sort of soft LD while you search for your more permanent hate.

With a second colour, you could give more creatures to the opponent, and more ways to punish tgem for getting creatures.

Black is probably the best way to punish the opponent. You get access to Rakdos Charm, Killing Wave, Trespasser's Curse, Blood Seeker, and Hissing Miasma.

White can help protect you until you draw your "I win" card via fog effects, plus there's a Blood Seaker like card in Suture Priest; creature donation in Mercy Killing; and if you run both B and W, Batwing Brume both fogs and drains.

Blue is one I want to tinker with next as it gives Hunted Phantasm, which gives five 1/1 Goblins to an opponent.

I also strongly suggest considering Dowsing Dagger. It's {2} to give an opponent two 0/2's with Defender.

Lol, the Repercussion + Blasphemous Act combo is cool. Sadly, Repercussion isn't Modern legal, which is a requirements for me to actually play this at my LGS (we only play Standard and Modern). I guess I could get a similar effect from cards like Rakdos Charm (which requires a splash of red) and / or Killing Wave (which competes with Stronghold Discipline for a slot).

There's another build I'm tinkering with which uses blue to include Hunted Phantasm (gives an opponent 5 1/1 Goblins). Problem I'm having is acquiring decent UB and WU lands...

Ok, I missed the Ruins, which btw also gets shut down by Moon. Seeing that blue is important on keeping Liquimetal viable, I strongly recomend embracing blue more. I know Splinter is a strong combo with Liquimetal, but other than that, is there any real need for green? Most / All other green artifact hate is easily substituted with red artifact hate.

This deck feels... incomplete?

You have the awesome Liquimetal + Artifact hate thing going, but no real way to search for or mimic Liquimetal. Ancient Stirrings helps "search" for Liquimetal and Myr Landshaper mimincs it pretty well.

Saheeli is your only blue card, why? It messes up your landbase, which is a big no-no, especially when mainboarding Blood Moon. Personally I'd drop Saheeli, but if you insist on keeping it, drop the Moons and embrace the blue by including cantrips like Serum Visions and Opt. (these cantrips take preference over Ancient Stirrings)

Crucible of Worlds + Ghost Quarter is a strong combo, but your own Moon shuts this down. Either remove Moon, or remove Crucible, Ghost Quarter can stay. Oh, btw, Ancient Stirrings can hit lands, so it can get you Crucible or Ghost Quarter.

Crumble to Dust is a sideboard card, and mostly (99.9% of the time) for one deck type: Tron.

Copied spells + the Storm mechanic is a common point of confusion. I ran a mono red Dragonstorm deck before Modern existed, so I looked up the rulings to see how I could manipulate them in my favour. If memory serves, there's a few copy effects that do add to a storm count, unless they've been errata'd since I last looked into it. I haven't played the deck since Seething Song got banned...

Rancor would fit well. +2/+0 and trample for {G} and it (almost) always returns to your hand when your creature dies. It's kind of "undying" too.

What would be the point if he already has those $100 worth of cards that you have not mentioned?

I ran a landfall deck in Standard not too long ago. It evolved from mono green at the start of Origins using Nissa, Vastwood Seer and Zendikar's Roil, to splashing green for Omnath, Locus of Rage and Chandra, Flamecaller. Eventually the landfall became a sub theme and I was running a RG Elemental ramp deck winning off Omnath's free 5/5's, its 3 damage for elementals dying, and Chandra, Flamecaller's [+1], eventually dropping Zendikar's Roil because of my club sideboarding mass -2/-2. The deck ran a lot of big value big Elementals like Gaea's Revenge and multiple land bonus stuff like Sylvan Advocate.

Chandra, Flamecaller is great as her [+1] works surprisingly well with Omnath's elemental trigger. While her own exile clause doesn't trigger Omnath, it does trigger if they are killed, meaning the opponent takes 6 damage regardless.

So I strongly suggest looking into some elemental and land based stuff that isn't strictly landfall and can provide big value. You also want some board sweepers, and being RG, mass burn is your best bet. Chandra, Flamecaller also doubles as a sweeper with her [-X].

Your land base is weird for a Ponza deck. In my Ponza deck I run:
4 Windswept Heath
4 Wooded Foothills
2 Stomping Ground
1 Cinder Glade
1 Mountain
9 Forest

Obviously overshadowed by Snappy and Bluehulk, but (as you said) in nonblue decks this should be a strong consideration. I run 3 in my Ponza deck and while it has a big affect on my spell selection (Mizzium Mortars instead of Bonfire of the Damned, etc), I have always been happy to see it.

On a note of it's Menace, personal experience has proven that most opponents forget about the menace, possibly because of the wall of text for its snap effect. Half way through a big tournament tends to cause even the most experienced people to make small mistakes like forgetting a single key word above a wall of text :p

I had considered Rimescale for flavour perposes, but went with this list because of their individual value.