Didn't thing Sol Ring would be on the list....

I'm sorry if I missed a previous post on this creature card, but I think Somberwald Sage might fit on your list.

Don't forget Scrying Sheets if you're wiling to run snow lands. puts snow cards into hand. is more hit or miss though.

Also now there is Kydele, Chosen of Kruphix, Thrasios, Triton Hero, and Kynaios and Tiro of Meletis thanks to C16.

The banner cycle? E.g. Mardu Banner

Yavimaya Elder is technically not ramp.

Why do you include the Obelisks but not Commander's Sphere, it's strictly better in EDH. Astral Cornucopia and Everflowing Chalice should both be on here as well especially with Atraxa, Praetors' Voice being a Commander.

Lotus Petal, Mox Opal and Chrome Mox are missing...and what I'm missing as well are all the important 1 drop mana elves, such as Arbor Elf, Noble Hierarch, Elves of Deep Shadow, Avacyn's Pilgrim, Fyndhorn Elves, Llanowar Elves, Boreal Druid and for two mana Bloom Tender. Carpet of Flowers is also a great card, even produces mana in the 2nd main phase on the same turn it has been played!

This list is missing a lot but for starters Regal Behemoth

Since Epoch isn't able to keep the list up-to-date, I took the liberty to generate a new list which I plan to maintain as much as possible. You can find the up-to-date list of all EDH ramp cards here.

Your imput and comments to keep this new list up to date are very welcome!

Any uses in Altar of Shadows? It's somewhat expensive, but it works for both mana, removal, and can be proliferated.

Hour of Promise is decent. I really like how it gets nonbasics like Tempt with Discovery

Thank you so much this list really helped my hydra deck.

Apprentice Wizard

Llanowar Elves, Elvish Mystic, Fyndhorn Elves, Arbor Elf, Joraga Treespeaker, Boreal Druid

Polishpat

For sacrifice decks:
Primal Growth, Viridian Emissary, (even Dawntreader Elk as a second Sakura-Tribe Elder)

For +1/+1 counter themed decks:
Gyre Sage, Rishkar, Peema Renegade, Devoted Druid

For multi-colored colored decks:
Quirion Elves, Sylvan Caryatid, Naga Vitalist, Servant of the Conduit, Rattleclaw Mystic, Deathcap Cultivator

Other:
Whisperer of the Wilds, Weaver of Currents

I can't believe you forgot Zhur-Taa Druid!

Still not mentioned:Herald of Leshrac, Retraced Image, The Keyrunes, Coldsteel Heart, Clear the Land, Into the Wilds, Oblivion Sower, Crypt of Agadeem, Deathrite Shaman, Thought Vessel, Plasm Capture, Mwonvuli Acid-Moss, Shefet Monitor, The Diamonds, Grand Architect, Scuttlemutt, The Totems, Citanul Hierophants, Cryptolith Rite, Sakura-Tribe Scout, Walking Atlas, Axebane Guardian, Overgrown Battlement, Oath of Lieges, Rites of Flourishing, Sasaya, Orochi Ascendant, Zendikar Resurgent, Squandered Resources, Food Chain, Overabundance, Vedalken Engineer, Cultivator's Caravan, Guardian Idol, Dreamstone Hedron, Koth of the Hammer, Pentad Prism, Sphere of the Suns, Qarsi Deceiver, Spectral Searchlight, Fellwar Stone, Channeler Initiate, Devoted Druid, Morselhoarder, Serra's Sanctum, Recross the Paths, Scattering Stroke, Cryptolith Fragment  ^Flip, Turnabout, Mana Drain

I feel like the Medallion cycle deserves a spot on this list.

Emerald Medallion

Jet Medallion

Pearl Medallion

Ruby Medallion

Sapphire Medallion

Traverse the Outlands

Kor Cartographer

Rofellos is not legal in EDH

Doubling Cube

Vizier of Tumbling Sands can be used to ramp