So chock this up to curiosity mixed with intentions for character creation with D&D 5E:

Main question I'm unaware about the answer to: What changed about Jace's outfit between SOI+EMN and all the other past and future appearances.

I'm trying to come up with a method of creating recognizable planeswalker characters as NPCs using the same method as PCs (one method offered in official product) while still giving them access to abilities that surpass their presumed classes limitations. Gideon's magic-fueled invincibility, Jace's free use of mind reading, Nissa's special elemental summoning, Kiora's summoning of MUCH larger sea creatures which don't always count as beasts and usually are much tougher than what is allowed, etc by keeping it to myself and simply making their equipment as Magic Items that grant fair access to these abilities (I'm aware Conjure Minor Elemental and Conjure Elemental are actual spells, and I'm sure Jace's telepathy are spells as well, but they seem to be treated as especially unique for them, as it doesn't seem Gideon LEARNED to go invincible or Jace LEARNED to read minds, they just discovered these powers within themselves, and it's not like the Sorcerer class has a Sorcerous Origin that covers invulnerability or passive mind reading from the get-go.

So far I GUESS I'd say Gideon's armor could count and costs spell slots or something
The Chain Veil for sure.
Dekella, Thassa's bident, however if Kiora made an appearance for a Zendikar campaign prior to her visit to Theros, than I'm unaware of how to give her exclusive Kraken-conjuring or what-not.
Nissa SEEMS to never be without her staff-sword thing, and it seems to have a spellcasting property to it, so fair
Chandra seems to have no power that couldn't be pulled off effectively by her simply playing like a Sorcerer multiclassing into Monk.
As for Jace, I would say his cloak, but unsure if his SOI garb was the same cloak or a tailor-made replacement

Any thoughts?