I don't think anyone expected Unclaimed Territory to become a Modern staple. But the format is large enough to support tribal decks, and once you commit to a single tribe, having a five-color land with little to no drawback is a powerful payoff.
But five-color aggro predates the emergence of the Human tribe as a viable deck in Modern. There are enough five-color lands to make the mana work, so long as you adhere to a few other restrictions in your deckbuilding.
One, which you have in common with Humans, is a commitment to running virtually all creatures with Ancient Ziggurat. Second is the commitment to a high density of multicolored creatures so you can leverage the power of Pillar of the Paruns. Humans decks get around their restrictions by playing Aether Vial, which its tribal lands can cast, but this deck gets to include Path to Exile, since most of its lands can produce the necessary white mana for the card.
In order to accelerate, it includes Birds of Paradise in addition to Noble Hierarch, so the deck takes the form of a traditional big aggro deck from the time before Wizards of the Coast saw fit to remove Llanowar Elves and the like from Standard. They were around for so long that having them seemed like a given, but the reality is that cheap mana creatures are incredibly powerful, enough so to make a splash even in a big format like Modern.
Past its mana creatures, this deck plays like a Who's Who of multicolored format staples, arguably a weaker distinction than being a Human. Voice of Resurgence; Anafenza, the Foremost; and Siege Rhino have already seen play together. Supplement them with Qasali Pridemage, Mantis Rider, and Falkenrath Aristocrat, and you have a deck that hits hard, even through disruption, and has enough disruption of its own to compete against unfair decks.
We're about to get a season of Standard where tribal decks are highlighted as Ixalan block takes center stage. Do we really need them taking over Modern as well? Just play the best creatures at every point on the curve and let the fact that there are a hundred great nonbasic lands in Modern take care of the rest.
In Modern, colors don't matter so long as you find the right lands. Most of the time, those lands are some combination of fetchlands and shocklands, but other combinations can be just as potent, so don't overlook them.
- 3 Tidehollow Sculler
- 4 Birds of Paradise
- 3 Falkenrath Aristocrat
- 4 Mantis Rider
- 4 Noble Hierarch
- 4 Qasali Pridemage
- 4 Siege Rhino
- 3 Spell Queller
- 4 Voice of Resurgence
- 3 Anafenza, the Foremost