The Tu’Narath illustration featured on the index page is the work of Adam Paquette; the Lady of Pain illustration used in the header and on the Wiki index is the work of Dana Knutson; and the works on the Adventure Log index and Act 1 Episode 7 are by Tony DiTerlizzi.
On the character page, the lightning bolt graphic used as the background for “Vidalok Natives” is the work of Teekatas S; the Faction Symbols are either the work of Knutson, DiTerlizzi, or a combination thereof (depending on whether or not they qualified as “interior artwork”); I can’t tell who the artist of that particular Sigil torus is, but I’m going to guess Rob Lazzaretti, as it was likely featured on a map fold-out (if not, DiTerlizzi is my second guess, because it looks like someone used white gouache for the hilights).
All other illustrations are the work of jredekop (i.e. “tic”).
The setting information within the “Multiverse” section of the Wiki is content from the Planescape setting books, used only for the purpose of running a game in that setting, or was created by the community on Planewalker.com. The Prime Material World of Vidalok was created by tic for its role in this game.
Planar Substitution Levels are from the 3.5e D&D source Planar Handbook. Skills are adapted from the Planewalker.com Planescape Campaign Setting. Feats are from the aforementioned Planescape Campaign Setting, and from the Eberron Campaign Setting. Spells are from the Planar Handbook and the Planescape Campaign Setting. Traits are from a variety of Pathfinder sources, fan creations from the Paizo or Planewalker boards, or created for this campaign by tic. Prestige Classes are adapted from the Planar Handbook, and from the Planescape Campaign Setting. Faction Abilities are adapted from the Planescape Campaign Setting. The Action Points system is from the Eberron Campaign Setting, and has undergone light conversion for use with Pathfinder classes.
Safira’s player characters were created by their players. Non-player characters were either created by tic, or are canon NPCs from the Planescape Setting (e.g. Shemeshka the Marauder is a part of Planescape canon). Some NPCs are lovingly adapted from figures on the Gatecrashers Neverwinter Nights server and appear in homage because tic loves them and their players.