The shift from building walls to making a place feel like yours is a fun design problem. A single lamp can make the same room feel like a workshop or a hideout. Are you leaning toward lighting as something players place and adjust themselves, or as part of the room themes?
I found Anton Seder's Das Thier in der decorativen Kunst (Vienna, 1896) on the Internet Archive, in a public-domain scan by the Getty Research Institute: dragons and sea serpents engraved like a naturalist's specimens and framed in...