Lands
Nykthos, Shrine to Nyx: Taps for colorless or lets us pay and generate equal to our devotion. This thing generates a lot of mana for us very frequently, and is honestly one of the best cards they made to support monocolor decks. I put this thing in basically all my monocolor decks that use mostly permanents.
Castle Garenbrig: Generates green mana and lets us pay to generate 6 that can only be used to cast creature spells or activate abilities of creatures. Comes in handy for letting us cast some bigger boys sooner.
Eldrazi Temple: Colorless land that can potentially generate for casting eldrazi. This card has come in handy but can be axed in favor of anything else. I personally like being able to get Void Winnower or Ulamog, the Ceaseless Hunger out a little quicker for the cost of a forest land, but there are plenty of alternatives you can put in here.
1 cmc
Fyndhorn Elves, Elvish Mystic, Llanowar Elves: Self explanatory. Cheap, 1 cmc mana producers that are quickly tutorable by Yisan and also help feed into some of the elvish synergy featured.
2 cmc
Priest of Titania: More elves = more mana. Sets us up for some power plays towards the midgame as well.
Incubation Druid: a 2 cmc elf that gives us one mana. If we pay 5, we can put some +1/+1 counters on it and can then generate three mana. The counters can get doubled by Kalonian Hydra.
Gyre Sage: A 2 cmc elf that doesn't do much until it gets some counters on it. We can easily proc it's evolve multiple times and Kalonian Hydra can make this thing get really big really fast, which also gives us a lot of mana.
Voyaging Satyr: A satyr that untaps a land. Has high synergy with some of our lands such as Nykthos, Shrine to Nyx or Mikokoro, Center of the Sea to draw more.
Nature's Lore: Fetches a forest and puts it in play untapped. Simple, effective, and enables some faster plays due to the land being untapped.
3 cmc
Llanowar Tribe: Powerful card that gives 3 green mana while costing three and being an elf. This card is really good at powering us up for some plays.
Selvala, Heart of the Wilds: Gives mana equal to the highest power among creatures we control and lets us draw a card if we get a creature that enters the battlefield with the greatest power. While this card can sometimes help opponents, it also helps us generate a lot of mana with the numerous big power creatures we have in the deck. Powerful and effective.
Elvish Archdruid: Generates mana for each elf we control as well as buffing other elves. Curving into this with a Priest of Titania allows us to generate large amounts of mana. The buffing power helps our elves trade with smaller creatures as well but usually it doesn't really matter.
Omnath, Locus of Mana: While not really a source of ramp, Omnath functions more like a bank. Loading this guy up with green mana can be an effective way to generate a wincon. Just be careful, because people will remove him quickly.
Cultivate: Puts a forest in play and sets up a land drop. Effective for amassing resources and curving up next turn.
Nissa's Pilgrimage: Similar to Cultivate except its better with more instants and sorceries in the graveyard. Usually this will basically operate like a cultivate, but sometimes we will get extra lands off of it.
4 CMC
Oracle of Mul Daya: Lets us play lands off the top and play an extra land each turn. It's also an elf so this gets affected by stuff like Priest of Titania. This card is honestly really good 90% of the time by not only ramping us up, but preventing mana flood draws. Very effective.
Goreclaw, Terror of Qal Sisma: Not really ramp, but reduces the cost of big creatures. Coupled with sources of ramp, this allows us to chain cast some big boys. With a draw engine, we can play tons of creatures back to back and still have stuff in hand. The fact this also gives attacking creatures +1/+1 and trample, makes this a really good card for our strategy.
Karametra's Acolyte: This card can generate A LOT of mana. Especially when paired with something like Llanowar Tribe where there is a lot of devotion. This card can set up some really powerful mid game plays. Curves nicely with Yisan too.
Skyshroud Claim: Fetches two forests at sorcery speed and puts them into play UNTAPPED. This card can be chained with some of our two cmc elves to generate some mana really fast. Very good resource generation.
Garruk Wildspeaker: His +1 Untaps two lands, which at worst gives us two more mana to use. At best, it enables some Nykthos, Shrine to Nyx power plays and lets us use stuff like Bonders' Enclave Multiple times. His -1 puts a 3/3 beast token out which is handy in a pinch. His -4 gives ALL your creatures +3/+3 and trample until end of turn. Useful for enabling cards like Impervious Greatwurm and Ulamog, the Ceaseless Hunger who have lots of power but no trample. Overall, this card gives us everything we want.
5 cmc
Freyalise, Llanowar's Fury: Solid card. Her +2 Generates Elf tokens that tap for 1 green and boost our other mana producers. Her -2 eliminates Artifacts or Enchantments. Her -6 is basically a Regal Force. This card can generate lots of value for us.
8 cmc
Vorinclex, Voice of Hunger: Doubles the mana our lands produce and makes opponents lands take longer. This thing is really annoying for our opponents the longer it stays around. Caution: Likely to induce salt from other players. I'd advise against bringing this thing out unless you can protect it, use the mana from it, or have nothing else to play.