Okay, while I feel it may assist my D&D design process, I also just am curious. From all lore (Uncharted Realms, interviews with Creative, flavor text, etc) What are the qualities that different planes' mana possess, either via their "feel" or their magical features?

From what I can recall:
Shandalar's mana is easily drawn upon, so magic is particularly commonplace.
Innistrad's mana is... eerie.
Zendikar's mana is volatile and has its own vitality
Ir's mana is potent in some way for the summoning of powerful creatures
Iquatana's mana is similar to Ir's? Or was that something else.
Alara's mana is complicated after the Conflux

Is there anything I'm missing?

Yes, but it's also quasi-sentient and can make itself inaccessible to people it doesn't like (which is what happened to Leshrac and Tevesh Szat in the comic when they came to Shandalar and tried to conquer it. That's... handy). I think it also says somewhere that the mana has a strong tendency to create elementals (which would make sense if it's quasi-sentient and so rich it practicaly oozes out of the land), but I can't for the life of me remember where exactly I read that.

According to Liliana, it's also particularly well suited for necromancy (which shouldn't surprise anyone). The "eerie" part is probably true but might also be in the eye of the beholder (and thus a classical case of "Shut up, Nissa!").


Yup.
That's actually just Turri Island, not Ir in general.

The plane is full of aether, which is probably what makes summoning easier.

Probably, but it might have recovered over time.

Lorwyn's mana is excellent for casting glamers. Drawing mana on modern day Kamigawa attracts the attention of the kami that live inside the land, which means tapping the land there without first appeasing the spirits is a really bad idea (isn't it, Jace?). Snow mana on Dominaria during the Ice Age was kinda slow and syrupy (and probably pretty cold IIRC), which is funny because Jeff Grubb basically described Snow mana in The Eternal Ice before it was really a thing in the card game! And of course the Rimewind mages developed their own branch of magic from its special icy qualities.

The source for at least some of this stuff can be found here: http://magic.wizards.com/en/articles/ar ... 2009-12-30

only Semi-related but on fiora i'm pretty sure all laws put into place by the monarch must be followed and I believe that has to do with the mana too? or maybe they just have very strong law magic there

Been a while since I read Agents of Artifice. Did Jace get attacked by kami when he tapped Kamigawa's mana?

The only evidence for Innistrad's mana being "eerie" is Nissa. I don't anyone else who's been there (aside from Nahiri, who just hates Innistrad period) seem to have an inherent problem with the mana.

We know via the core set that soul of innistrad is more or less black mana based, which would explain why Lilliana loves it/why Nissa hates it. Also, when Nissa was tapping into the mana the plane was pretty eldrazi infested, which could explain the eeriness.

Im not sure the soul of X cards are the best thing to look at for any sort of flavor connection.

No. But he could feel Kami within the plane whenever he probed it for mana connections. IIRC he avoided making connections on Kamigawa, lest he accidentally set a kami off.

This, considering soul of shandalar was literally just signed the leftovers when they decided not to make it soul of Tarkir.
Besides, we already know soul of ravnica isn't blue either.

The souls of whatever were an absolute disaster flavorwise.

Except the Soul of Mercadia I made.