I have this idea for a project where I am going to make a bunch of two color decks all intended to be played against each other and loaned out to friends, either for learning magic or for big multiplayer games. I wanted to make 10 decks, each of which a unique color pair, and featuring cards from a certain plane. So, which planes go to which color pairs best?

So far I am thinking:
: Paliano - Monarch theme
: Amonkhet - Embalm theme
: Innistrad - Graveyard/zombie theme
: zendikar - Landfall/awaken theme
: Ravnica - Izzet spells shenanigans
: New Phyrexia - Infect

could do UB lorwyn/shadowmoore fairies

oh nevermind you already have UB

god rag you are worthless

So you still need , , ,
Do the decks have to embody the plane as a whole, or just some facet of it?
Ixalan is looking pretty if you feel like waiting.

God rag, stop saying you are worthless.

Theros and Devotion seems a fit (better than Bestow). Of the pairs unclaimed I'd probably do GW, with focus on green permanents (and Aspect of Hydra) and the white mostly for its nonpermanent spells.

Tarkir -> Kolaghan and Zurgo Dash Aggro? The Khans version of the plane doesn't work terribly well for 2-color decks (it wants 3) and with that you probably lose Morph, so best bet is likely to pick a Dragons-timeline dragon and run with its pair (so that knocks out enemy color pairs). Even if I didn't push GW for Theros above, I'd rather Dash represent the Tarkir plane, rather than Bolster.

Kaladesh RW DwarvesVehicles starring Depala?

You could easily put together GU hybrids from Shadowmoor (all those cards that benefit both G and U creatures, are triggered by both-G-and-U spells, count control of island and forests...) , at least as a stand-in until you have the cards for Ixalan GU Merfolk.

Here's my go of it!

Dominaria (Time Spiral) - - Suspend
Mirrodin/New Phyrexia - - Proliferate
Lorwyn/Shadowmoor - - Treefolk & Untap
Alara - Devour/Dragons
Innistrad - Flashback
Zendikar - Landfall/Allies
Amonkhet - - Exert
Kaladesh - - Fabricate
Ravnica - - Dimir (mill)
Paliano - - Monarch
Tarkir - - Raid

You want a good mix of agroo, control, and high-synergy decks; I recommend at least three of each? ish? idk? you know what i mean?

I am completely willing to change around pairs I had already chosen, and I'd like the pair to embody one of the more memorable faucets of the plane if possible. I also really want paliano in there because monarch and voting are fun multiplayer mechanics

: Alara - Devour/Sacrifice
: Dominaria - Cats (You get to use Jedit Ojanen of Efrava and/or Mirri, Cat Warrior or Duelist, but we all know the MVC will be Savannah Lions)
: Theros - Heroics
: Kaladesh - Whale Watchers (remember to travel light)

I agree with your first two (though since you can run Unearth in the Rakdos combo, might as well), but I'd make the either Shadowmoor, Ixalan merfolk, or MaRo's first deck.
For , I'd either make it Mirran equipment/battle cry/metalcraft (mixing in cards from Mirrodin blocks 1 and 2), or Kaladesh Vehicles.

Please not that

Let's see then. Problem is, not a lot of other planes make me think Red/Blue right of the top of my head. Exception is the Izzet for Ravnica, but Ravnica's got such strong two-colour personalities that I tend to think of SO MANY mixes when thinking of them (First to come to mind are Dimir, Azorious, Orzhov, Dimir, then Golgari, in that order). Could put Blue-Red into Ravnica for Overload and spells-matter type deck. Time Spiral had so much going on in it that it's hard to otherwise pick out a strong mechanic from the set. Guess you could do Kamigawa-theme with Blue/Red Arcane, but I wasn't in Magic back then, so I don't really know if that would work.

Tarkir Prowess maybe?

For your consideration

I avoided revisiting Mirrodin because New Phyrexia is technically Mirrodin post-Phyrexian takeover.
Which means he could get away with using cards from original Mirrodin to fill out the deck, most likely with stuff like Wrench Mind, Bloodscent, or Devour in Shadow. But that's just my opinion.

But yeah, my Whale Watchers idea probably isn't newbie friendly. And the version I've played tends to piss a lot of people off at my LGS, so if the goal is multiplayer fun it's definitely a bad idea.

The horse sorta left the barn...I got bored and made a WR deck already (at "for your consideration" above). I'm not sure how intro-friendly it is either.

If you want Beginner decks I've also done that elsewhere in NGA

I'm not sure I like the idea of mixing New Phyrexian cards with 1st-Mirrodin block cards, which are by definition Mirran. If I was going to mix them with anything, it'd be Phyrexian or poison cards from other blocks. IMO, Phyrexian is about as different from Mirran as any plane is from any one other plane.

So here is where I am at currently:

- New Phyrexia - Infect/proliferate
- Kaladesh - Energy/artifacts
- Ravnica/izzet - Spell shenanigans
- Amonkhet - Embalm
- Paliano - monarch/voting
- Zendikar - Landfall/awaken
- innistrad - Graveyard shenanigans
- Lorwyn - Giants
- Theros - Bestow/heroic
- Ixalan - Pirates

The last three I feel the least strongly about, but I'm pretty happy with the top seven decks. Also, I did consider going with exert as the theme for amonkhet, but embalm just seems too evocative of egypt: the plane to pass up.

For the last 3 you could do:

- Lorwyn - Goblins
- Theros - Heroic Aggro
- Ixalan - Dinos Ramp

: New Phyrexia
: Kaladesh
: Paliano
: Zendikar

I think these are fine. Possible options for the last six:
: Lorwyn [Elves], Amonkhet [-1/-1], Ixalan [Explore], Ravnica [Golgari], Innistrad [Delirium]
: Dominaria [Suspend/Storm], Kamigawa [Arcane], Mirrodin [Affinity], Ixalan [Pirates], Innistrad [Flashback], Ravnica [Izzet]
: Ixalan [Dinosaurs], Lorwyn [Giants] Theros [Heroic], Amonkhet [Exert], Ravnica [Boros]
: Ixalan [Dinosaurs], Innistrad [Humans], Amonkhet [Exert], Tarkir [Bolster], Ravnica [Selesnya], Kamigawa [Spirits]
: Ixalan [Pirates], Lorwyn [Goblins], Lorwyn [Flamekin], Innistrad [Vampires], Tarkir [Dash], Ravnica [Rakdos]
: Tarkir [Prowess/Rebound], Lorwyn [Merfolk], Innistrad [Spirits], Ravnica [Azorius], Theros [Heroic]

I would probably do:
Tarkir
Theros
Amonkhet
Dominaria // Kamigawa
Ixalan // Lorwyn
Innistrad

ravnica is overrated anyway
BG feels more appropriate for Amonkhet, but Exert is a baller mechanic, and all the other GW archetypes were lame.

I'm going to give my suggestions here, as a flavor person. I like Zendikar (Perhaps with Omnath, Locus of Rage), Fiora (The plane where Paliano is the big city), Innistrad, and NPH (Though I feel like tricolor more caputes its essence). Amonkhet... WU Embalm will works as a deck and probably be fun, but it feels weird to use a color outside Bolas' identity for Amonkhet. Similarly, using the Izzet as the touchstone for Ravnica feels strange. The Azorius are the most tied into the magic of the guildpact and the protagonist of the first Rav block was Boros along with the Legion being Gideon's hook in RtR, so I'd probably use one of those guilds before the Izzet

This is what I would have thought, taking your list as inspiration...

Ravnica, Grand Arbiter Augustin IV/Intro to Control (Can contain Soul of Ravnica)
Innistrad, Gisa and Geralf/Skaabs (Can contain Soul of Innistrad)
Amonkhet, Neheb, the Worthy/Heckbent/Sligh (Could use Hazoret the Fervent)
Zendikar, Omnath, Locus of Rage/Landfall/Lands Matter (Can Contain Soul of Zendikar)
Tarkir, Abzan/Dromoka +1/+1 Counters
Theros, Enchantments Matter possibly with Athreos, God of Passage. Gets the best Constellation cards and also Soul of Theros
Shandalar. Since Amonkhet is taking the "Suicide" aggro theme, perhaps Equipment? The support here is from Magic 20XX. Also can have Soul of Shandalar
Kaladesh Reclusive Artificer/Artifacts Matter
Kamigawa Spiritcraft/Spirit-or-arcane, Blue-green is where most of the support for the theme lived. You'll have to work to optimize this though.
New Phyrexia Infect (Can contain Soul of New Phyrexia)