Here are my current scattered notes on the mechanical side:
General:Everyone speaks
Umbral for free
Ethereal plane: Assume you still have access to abilities depending on the ethereal plane through discorporation
Races that are native to the plane:Arima Gargoyles - free bonus feat
Dark Creeper - LA+2
Dark Stalker - LA+3
Half-Kermohryg - LA+0
Illumians - free bonus feat
Planetouched, Jukurche - LA+0 (or lesser planetouched w/ free bonus feat)
Shadar-Kai - LA+1
Shadowswyft - LA+0 (or lesser planetouched w/ free bonus feat)
Templates:Dark Creature - LA+0
Necropolitan - no XP and gold costs
Shadow Creature - LA+1. Jukurche and Shadowswyfts can become Shadow Creatures despite being outsiders
Shade Template = not suitable for PCs
Umbral Creature = not suitable for PCs
Special animal companions / familiarsDark Creature template for free? (Free Shadow Creature for familiars of Shadowcasters?)
Beacon Moth (Dragon Mag #322 p.20)
E6 homebrew: Beacon Mothlet (improved familiar lvl3)
Ecalypse (Manual of the Planes p.170f)
E6 homebrew: Duskmane (requires ride check DC 24)
Base classes:Shadowcasters beefed up
Familiars gain Shadow Creature template?
https://forums.giantitp.com/showthread.php?353464-Shadowcaster-Remixoriginal terrible Shadowcaster as low tier alternative?
Sha'ir with access to Shadow Gens - genie-related abilities actually useful with khayal genie trading posts
https://dnd-wiki.org/wiki/Shadow_Gen_(3.5e_Monster)
Dragon Shaman alternate totem Shadow Dragon
http://www.mit.edu/~locutus/DnD/classes/TotemDragons.htmlPrestige classes:Shadowcraft Mage available to non-gnomes
Spells:Shadow Elementals as a summoning option for SNA/Summon Monster
Rickshaw (Sor/Wiz 1, Wu jen 1)
Palanquin Procession (Sor/Wiz 3, Wu Jen 3)
Overland travel is as fast on the Plane of Shadow whether walking, flying or on horseback. It has become a status symbol of the wealthy to travel well-rested by sitting in a palanquin.