Why have anything to cast in your library, if you have other players’ libraries to work with.
Each color has its distinctive features and one of the features for green is its ability to ramp. Sure, all colors can produce extra mana in some way or another, but green is definitely the master of this, having several ways of doing it in most sets.
However, since I don’t want to go through all the ways green can do this (mana elves, doubling effects), I’m limiting this to noncreature cards that put lands into play from your library and are green (there are some white and colorless ones that do this as well). I’ll probably do a separate one on creatures at some point. I’ll also omit all the spells, that don’t actually add lands, but rather change the ones you already have into different ones, like Scapeshift which could be used to produce more mana in many ways, but generally isn’t.
This is up until Ixalan.
One of the problems in recent history was that there weren’t really good four mana green creatures. Why was that a problem? Because there were plenty of two costing mana elves. If you play those, you want to play a four drop to play on turn three. Sure, there is Bristling Hydra, which is still quite strong, but there’s some new ones in the new set. (Actually, Crocodile of the Crossing is quite underappreciated as well.)
No Elven Mystic available, but that part of Standard seems to be permanently over. However, there is several fairly efficient manaproducers in the format, like Servant of the Conduit and Rishkar, Peema Renegade and then there’s these two:
There’s also Kiora, Master of the Depths, which might work, but I wouldn’t bet on it.
So, how do we keep going with the first ability? Well, here’s an idea: The iconic creature for green is hydra. Make a larger one each turn.