Wikipedia states that:
"Steampunk is a subgenre of fantasy and speculative fiction which came into prominence in the 1980s and early 1990s. The term denotes works set in an era or world where steam power is still widely used—usually the 19th century, and often set in Victorian era England—but with prominent elements of either science fiction or fantasy, such as fictional technological inventions like those found in the works of H. G. Wells, or real technological developments like the computer occurring at an earlier date. Other examples of steampunk contain alternate history-style presentations of "the path not taken" of such technology as dirigibles or analog computers; these frequently are presented in an idealized light, or a presumption of functionality. It is often associated with cyberpunk and shares a similar fanbase and theme of rebellion, but developed as a separate movement (though both have considerable influence on each other). Apart from time period and level of technological development, the main difference between cyberpunk and steampunk is that steampunk settings tend to be less obviously dystopian."
Our game is going to be set in the 19th century, so here is a list of books that are steampunk in the 19th century:
19th century setting
Novels set in the Victorian era include:
· Against the Day by Thomas Pynchon (2006)
· Anti-Ice by Stephen Baxter (1993)
· The Anubis Gates by Tim Powers (1983)
· Celestial Voyages series (2003) by Jeff Provine -- Interplanetary expeditions are launched in 1901.
· The Difference Engine (1990) by William Gibson & Bruce Sterling -- the designs of Charles Babbage led to the wide usage of mechanical computers in Victorian England.
· Fata Morgana by William Kotzwinkle (1977)
· Homunculus by James Blaylock (1986)
· Imperial Moon by Christopher Bulis (1980) -- A Doctor Who novel set in 1897 when Queen
· Infernal Devices by K. W. Jeter (1987)
· Lord Kelvin's Machine by James Blaylock (1992)
· "Ned the Seal" trilogy by Joe R. Lansdale:
· Zeppelins West (2001) 
· The Sky Done Ripped (TBA)
· The Steampunk Trilogy by Paul Di Filippo (1995)