
OK... you got to electricity, which i wanted to add, but i'd like to further build on that by saying
- direct current (AC is "modern")
- giant humming transformers
- giant clicking relays and frankenstein guillotine power switches
- faraday cages & tesla coils
- tubes, tubes and more tubes
- big lead acid batteries
- oil & paper capacitors
you might also revisit the SOURCE of where electricity was discovered, the torpedo fish

don't forget windmills, watermills, whatever those grinders where a mule etc. harnessed to a pole they walk in circles around are called. mechanical energy is energy... otherwise... what are all those gears for in steampunk? right?
why not use bioluminescence? it occurs in nature
there's no reason that modern, even futuristic tech can't make it into a steampunk story. antigravity would be a feature of the alternate timeline story i'm TRYING to write. new timeline = why does the story have to be limited to pre-1990 tech? why can't their be solar panels in a story?
electricity comes from clean hydrogen burning steam generators in my world, though now, i'm thinking of adding solar.
speaking of generators & solar... solar steam is STEAMPUNK... duh!

solar stirling engines are totally steampunk too

you could also use drinking bird tech...

chemical energy through heat and expansion etc.
solar algae generating fuels
geothermal