The only things I can think of are Karn's Bastion combined with either Blast Zone or Hickory Woodlot/Saprazzan Skerry. These aren’t super combos, but this is what you get when you try to find land-only combos. The Vivid cycle would also work with the bastion but isn’t better than dual lands in a 2 color deck.
A quick note: These combos are not super useful. The first pays 5 to avoid paying 3 (counting the land tap as 1 mana), and the second...I just realized it doesn’t really work well in your deck. So both of them are really only useful if you need proliferate anyway.
Other than the above, the only combo I can think of is the Tron lands.
November 24, 2020 7:22 a.m.
(Use thespian stage to copy dark depths, keep the thespian stage copy due to the legendary rule. It doesn't enter the battlefield this way, so it has no counters, and you immediately sacrifice it for a 20/20 indestructible Marit Lage token.)
November 24, 2020 7:36 a.m.
I’m dumb! Thespians! How could I forget! I feel dumb! Aaaaa
November 24, 2020 7:39 a.m.
Field of the Dead + Vesuva + Thespian's Stage can be pretty backbreaking, especially if you are running lots of fetches, things that allow you to play multiple lands a turn such as Cultivate or Azusa, Lost but Seeking, Crucible of Worlds effects, and things like Ancient Greenwarden. Oboro, Palace in the Clouds is a great option because as long as you have your commander, it isn't a dead card, and it also plays into the Field of the Dead (or any land combo that involves a land entering the battlefield) - consistently ensuring you have a land each turn.
November 24, 2020 10:49 a.m.
Cards that allow you to consistently tutor up and non-basic land combo pieces your are looking for include Expedition Map, Crop Rotation, Sylvan Scrying, Reap and Sow, Primeval Titan, Tempt with Discovery, Hour of Promise, and Nylea's Intervention. I'm sure there is more, but these are what come to mind.
November 24, 2020 11:01 a.m. Edited.
A land I think is underplayed is Glacial Chasm - there is a lot you can do with it if you decide to run any effects that prevent it from gaining counters or if you have decks that allow you to easily pay lots of life.
November 24, 2020 11:05 a.m.
Halls of Mist is fun, Maze of Ith, Mystifying Maze, Labyrinth of Skophos all deal with attackers. Another way to deal with creatures is with removal: enter Quicksand and Mouth of Ronom. When protecting your own creatures Yavimaya Hollow is the best. With your general being a 6/6 Arena will kill quite a few unfortunate souls.
Soldevi Excavations is good filtering on a land, Search for Azcanta Flip is great for finding noncreature spells; however, note that it also cannot get lands. Halimar Depths is a one time top deck filter, you have to decide whether entering tapped is small enough to ignore. Castle Vantress is going to be the best land for this, four mana plus a tap is expensive though.
All creature lands are great, but given enough mana Urza's Factory is even better, just pumping out creatures. Hostile Desert takes advantage of all the lands that will undoubtedly be entering your graveyard. Of course the aforementioned Field of the Dead is the best at generating blockers and possibly attackers.