Of the top of my head, without studying:

I could make soap and biodiesel from wood ash and olive oil... Though I'm not sure which one, lol.

I could also make some batteries, a basic generator/motor, etc.

Some basic chemistry. I could make hydrogen which I'm sure would be a crowd pleaser.

I could most likely muddle through my math to contribute some stuff that's unknown at the time, I could definitely "invent" a bunch of algorithms, data structures, encodings. I could also atleast describe a functioning CPU/computer. Maybe I could figure out how to make vacuum tubes? I'm sure I could find a glass blower to make the tubes themselves, but I'm not sure what material you'd need for the filaments, or how to pull a vacuum. I could most likely make a mechanical computer, or even adder/counter with enough time. Introducing Arab numerals could be big.

I could make a telegraph If I get steady electricity figured out, hell, maybe even a telephone. Sadly I'm not really sure how radio works.

Some basic economics/astronomy/cosmology/philosophy/sociology/political theory/evolution might not be immediately relevant, but if I write it down folks might find it interesting in a few hundred years after the fact.

I could also describe a nuclear reactor and nuclear bomb in broad strokes, along with firearms I suppose. I'm pretty sure gunpowder is charcoal and something with nitrogen right, potash, or is it a nitrogen containing mineral you dig out of the ground right? You can make a type of solid rocket fuel with sugar and iron rust, right? Maybe I could make chlorine gas, since that's just hydrolyzing molten salt, right?.

I think I could make a laythe? And therefore a piston which I could use to make a steam engine, put that on tracks or a boat. And y'know of course Cannons if I get gunpowder figured out.

You can mass produce steel or iron by pumping air through iron ore and coal/charcoal right?

I could make a simple printing press, maybe even a rotary one. Oh yeah, and paper making!

Maybe I could make a telescope, use the moon's of Jupiter to get accurate time keeping and do accurate cartography, along with knowing about the Americas, general Asian geography, Australia, etc. Maybe I could make a somewhat accurate maritime clock knowing that the guy who originally made one used strips of metal to adjust the clock speed at different temperatures to handle thermal expansion of components? That would help help solve the longitude problem? How accurate are capacitor clocks?

I'm also mid transition Trans, so I'm not sure how that would go down. Hopefully the Greeks are less witch burny. You can make HRT with concentrated female horse urine, right?

Convincing folks to brush there teeth could be big. Ntm washing hands and a germ theory of medicine. To bad I have no idea how to make anti-biotics, but maybe I could set others in the right direction. Though it's fairly simple to make petri dishes and isolate cultures right? The petri dish is just boiled gelatin made with sugar and beef broth poured into a container which can be somewhat easily sealed, maybe with wax?

If I have the resources sending some folks to the new world to pick up potatoes, corn, and beans would be great. Some basic nutrition advice could be good, the importance of vitamin C, vitamin A, macronutrients etc.

Maybe I could make some sheepskin condoms and introduce some family planning concepts/ plus some basic sex ed?

I might be able to organize a few manufactureries using division of labor/production lines with the help of some local artisans, then maybe do some light mechanization using water power atleast, or steam power if I get that figured out. Also ntm designing based on replaceable parts could be big.

Maybe I could make a mechanical loom if I tinker away at it?

I know how an ic engine works in principal, but I'm not sure I could make one without a machine shop. Maybe I could make an electric tractor plugged into a watermill generator or something?