Dark Sun rogues come from all walks of life: slave, freeman, merchant and noble. Rogues are common amongst merchant houses as astute guides, shrewd bargainers, and smugglers. Every city-state has a thieves' guild, and they often deal with wizards (no questions asked), who pay fees not only for illegal components but for protection and anonymity. Skilled rogue performers are referred to as "bards," with the presumption they might also be serving as a covert agent or assassin. Poison has no stigma on Athas and likely to be used by any rogue.
Use the defaults from the Player's Handbook or Xanathar's unless changes are mentioned below. From any other book please check with the DM.
Arcane Trickster. Does not exist.