So, I've been out of standard for about a year now, and with Lenowar Elves and the 5/4 for 3 being spoiled, I decided I wanted to try and get back in it.
The basic strategy of this deck is to bring out as many big powered creatures, as fast as possible, and swarm the field, before dealing quick damage to the opponent, ideally before control can even get started, before bringing out a Ghalta on turn 4/5. Here are my reasonings for each card.
One Drops: Greenbelt Rampager: Its a 3/4 on turn 2. Dodges lighting strike, harnessed lightning and abrade pretty well.
Blossoming Defence: Because removal, and occasionally helps to deal that last 2 points of damage
Prey Upon: Not my favorite card, but the closest thing to removal mono-green gets. Potentially should be replaced with something else.
2-Drops:
Merfolk Branchwalker: One of the best engines in the deck. We run a lot of duplicate legends, so being able to send them to the grave is usually good. Also helps ensure we hit our lands and prevents topdecking.
Rhonas's Last Stand: I'm probably heavily overvalueing this card, but its a 5/4 on turn 2, that only can be hit by fatal push and Vraska's Contempt. The lands not uptapping stinks, but we have enough 1 drops that I can still usually do something. Gets a lot better once Elves is reprinted.
3-Drops (Now we start cooking):
Jadelight Ranger: Same reasons as branchwalker but even better
Rhonas: Having a creature with power 5+ is easy for this deck. Being able to instantly put trample on a creature is fantastic.
Wayward Swordtooth: Not that great, but ascending on turn 4-5 isn't too difficult for the deck, and it synergizes well with Prey Upon, Ghaltia, and Rhonas.
Rhonas's Monument: I argued with myself over this one. If I don't have the nut hand starting off, it can put in a lot of value. It synergizes well with Rampager, and the temporary boost can make almost every creature in the deck able to turn on Rhonas. Probably should be running the full playset, but its legendary and that makes me nervous.
5-Drops:
Verdous Gearhulk: I really debated on this one, and if something gets cut, I think this one should be it. I can get it down turn 4 if I'm holding 5 lands, and have Swordtooth out. The counters and trample are nice too.
12-Drops:
Ghalta: The best card in the deck in my opinion. Getting it out early seems really easy for this deck, and having a 12/12 trampler is usually enough to get most opponents to scoop unless they have an answer. Maybe I shouldn't be running 4, but I can't resist.
Sideboard: I'm really uncertain about it, especially coming back into standard after not playing for awhile. If you have any suggestions or notice something missing, please let me know.
