I suspect a lot of the relatively common steampunk and "dungeon punk" fantasy miniatures could be modified into more of a clockwork aesthetic, especially if you can source some small, cheap gears to dress stuff up with. You can apparently find large batches of cheap gears marketed to steampunk cosplayers and the like in craft shops, Amazon, Etsy, and the like.
Fantasy figures that might come in handy range from gothic horror figures (vampires, werewolves, mummies, witches, ghosts, ghouls, zombies, etc.) which are often dressed in ambiguously Victorian costumes that probably won't look far out of place in a weird Napoleonic setting. Reaper's inexpensive plastic Bones product line supplies a lot of these sorts of monsters, and they kitbash really nicely with Wargames Atlantic bits.
"Gaslight" Cthulhu investigators (some costumes might be a bit anachronistic, but others might work), and golems and "warforged" mechanical men who can be customized to fit a more Napoleonic aesthetic. Above are some examples of Reaper Miniatures' "Bones" plastic Mythos investigators from Chronoscope. Some are pretty clearly from a later historical period, while others - such as the great camel, the hillbilly, and the "gaslight" era figures toward the middle in long dresses or top hats might not be far out of place in a weird Napoleonic setting! (Naturally, the Cthulhu Mythos monsters by the same company could also fit the setting, for some REALLY weird additions!)
Reaper Miniatures makes this (metal) "robot butler", along with other golems, robots, and other figures that might be suitable (look for their "Chronoscope" line for some steampunk style characters who might be fudged into service for the earlier Napoleonic era!)
Also look for Reaper's "Brinewind" and other pirate-themed miniatures, as these, too, wouldn't be far out of place in the Napoleonic era. (I don't know much about the history of sailing ship technology, but Reaper's Sophie's Revenge pirate ship seems to me like it would look great even in a historical Napoleonic setting, and would surely work even better in a weird Napoleonic setting!)
Reaper also makes this great cyborg super-ape, Ape-X, both in "Bones" plastic, and in traditional white metal! He would be equally at home in a futuristic sci-fi setting, a steampunk setting, or weird Napoleonic setting, IMHO, acting as the intimidating muscle behind a criminal mastermind with a talent for weird science....
Wargames Atlantic's Napoleonic figures are a pretty obvious place to look for some great soldier figures. There are also some obvious "Death Fields" choices, such as the Grognards, and even the upcoming Bulldogs. The "Death Fields Accessory Sprue" includes some great laser-gun bits and other gear (like mechanical arms) that can be added to Napoleonic and other soldiers to give them more of a sci-fi look - "death rays", pneumatic guns, and the like are possible reinterpretations that might explain these bits.
Some less obvious Wargames Atlantic figures that could fit the setting include the upcoming Boxer rebels, and the fantastic and versatile Afghans. TIP: both of these kits can be "kitbashed" with the two plastic Frostrage Wizards kits to add spellbooks, staves, potion bottles, and other magical gear; Death Fields sci-fi bits are also an option. (Such figures would look right at home as pulp-style villains - see Fu-Manchu, Abdhul Alhazred, Ming the Merciless, etc. - but I'm sure we're all inventive enough to find creative ways to do something a little more nuanced and original than playing the dated "Yellow Peril" trope straight. Lo-Xan: Vampire Hunter, and his airship crew! Abdhul Abbar: Mythos Investigator and his robot-butler sidekick!)
The lizard-men seem would surely fit right into a Napoleonic setting, as-is!
Try kit-bashing the Wargames Atlantic Halflings with some Grognard heads and weapons, and/or some Napoleonic bitz... something tells me a Halfling in a Napoleon hat would look fantastic! Re-arming the short-armed halflings with human-sized muskets might be tricky, but I'm sure someone can work it out....
