First of all, great guide.
I am pretty sure the following list was already posted somewhere on this forum but I wasn’t able to find it today.
This list is copied from our Rainmakers facebook page. Hope it will add usefull information to this guide.
I will also have everything together on one place 
Sorts of Traitstones you get when:
- invading this Kingdom
- playing Challenges/Quests in this Kingdom
- Revenging with this as your home Kingdom
Adana: Fire / Wind
Broken Spire: Water / Earth
Darkstone: Earth / Magic
Divinion Fields: Magic / Wind
Forrest of Thorns: Nature
Ghulvania: Magic / Fire
Grosh-Nak: Fire / Earth
Karakoth: Magic
Khaziel: Earth
Khetar: Water / Magic
Maugrim Woods: Nature / Water
Mist of Scales: Water / Fire
Pan’s Vale: Nature / Wind
Pridelands: Fire
Stormheim: Water
Sword’s Edge: Water / Wind
Whitehelm: Wind
Wild Plains: Fire / Nature
Zaejin: Earth / Nature
Zhul’Kari: Nature / Magic
Arcane Traitstones:
Arcane Stoic Traitstone: Stormheim
Arcane Swamp Traitstone: Maugrim Woods
Arcane Blood Traitstone: Mist of Scales
Arcane Blade Traitstone: Swords Edge
Arcane Spirit Traitstone: Khetar
Arcane Shield Traitstone: Broken Spire
Arcane Stealth Traitstone: Forrest of Thorns
Arcane Beast Traitstone: Wild Plains
Arcane Light Traitstone: Pan’s Vale
Arcane Venom Traitstone: Zhul’Kari
Arcane Forest Traitstone: Zaejin
Arcane Rage Traitstone: Pridelands
Arcane Storm Traitstone: Adana
Arcane Dark Traitstone: Ghulvania
Arcane Lava Traitstone: Grosh-Nak
Arcane Summer Traitstone: Whitehelm
Arcane Plains Traitstone: Divinion Fields
Arcane Death Traitstone: Karakoth
Arcane Skull Traitstone: Darkstone
Arcane Deep Traitstone: Khaziel
Arcane Mountain Traitstone: No Kingdom available yet (Needs Earth / Wind) so that might be the next kingdoms banner