tart listing instances where you can refuse a quest reward.
Icewind Dale (in which it is literally forced upon you by game mechanics), Icewind Dale 2 Targon, Baldur's Gate multiple instances (e.g. Ankheg-quest), Pillars of Eternity most quests (e.g. The Final Act), The Witcher games multiple instances (e.g. To Bait a Forktail or Shrieker), almost all Dragon: Age quests (interestingly, this game will almost never penalize you for demanding a reward or benefit you for being charitable in keeping with the grimdark theme), Baldur's Gate 2 multiple instances (e.g. rescuing the harper, in which refusing a reward will actually net you the biggest reward), Neverwinter Nights 2 most quests (e.g. Bandit Camp/Liza).
In fact, I'd be hard pressed to provide an example of any RPG remotely like Black Geyser without reward refusal. Completely baffling to me that you'd view this as a unique feature.