The key aspect of Victorian Science Fiction is the SCIENCE! Anachronistic science, violating the laws of physics, incredible advances and imaginary substances all play their part in the development of the fantastic technologies that appear everywhere in VSF. You want examples?
Liftwood. From Space: 1889, this miraculous substance is a wood that grows only on Mars, and has anti-gravitational properties. Rare and expensive, it is still favored for the construction of sky galleons. Sadly, it doesn't work on Venus, deteriorating at an incredible rate.
Unobtainite. My own creation. Run an electric current through this naturally occuring element (which forms blue crystals) and it repels gravity. More current, more repulsion. Great for making flying vehicles, and less fragile than liftwood.
Cavorite. From H.G. Wells, cavorite is a metal that pushes against gravity unless shielded from it. Used by Professor Cavor to ascend to the moon.
Radium engines. Verne used radium engines (essentially, atomic reactors) to power the Nautilus. Heck, the Nautilus itself was an anachronism of wonderfully weird science. I like the Disney version.
Babbage's Difference Engines. While this idea really existed, it was never fully developed. In essence, a mechanical computer. In VSF, not only did Babbage perfect it, it has been made ever smaller and more powerful, until it fits in the body of a man-sized (or smaller!) automaton.
Flying Ships, forts, etc. Either airships (lighter than air) or liftwood, or unobtainite, or cavorite... it doesn't matter, we like ships that fly. And not just small balloons, but big armored warships. Robur thought he could conquer the world from his. A very popular game (Dystopian Wars) is currently in production around the concept that flying dreadnoughts are cool. Because they are.
Automatons. Mechanical servitors, often steam powered, but also clockwork based. These can be man-sized, or smaller, or even much larger. Mad geniuses build them to conquer the world, huge companies market them to the public, and to industry.
|Maton's Halfjacks, a Work in Progress photo|
Walkers. Walking vehicles are another favorite of the genre. From one man conveyances to massive four-legged (or more!) armoured behemoths, the walker is just fun. Powered by steam, of course.
|The engine for HMLS Gargantua, by Colonel O'Truth|
I love the flywheel.
Landships. The last item of weird science I will mention here is the ubiquitous landship. Early tanks would appear only a few decades after the real Victorian era, and armoured land trains using steam traction engines had been used already against the Boers. So we just bump that up a bit, add in the improvements in turreted weapons from the 1930s, power it all by steam, and cover it in riveted armour. Can't forget the rivets! Almost everyone in VSF gaming has at least one of thses bad boys. I have several, in different scales.