One-Man Industrial Revolution

The Gadgeteer Genius is good at what he does, but he doesn't have a particularly profound effect on The Verse, because Reed Richards Is Useless. This guy, however, is almost singlehandedly responsible for ending the Medieval Stasis: the one person responsible for all the high technology in a setting. Anyone Giving Radio to The Romans is likely to be this. See also Alternate Universe Reed Richards Is Awesome.

Anime and Manga

 * Dr. Vegapunk of One Piece is the primary reason the Ocean Punk setting has Frickin Laser Beams.
 * Or rather why the World Government's Hollywood Cyborg(s) can use them besides the original wielder of said beams.
 * Dornkirk, from Vision of Escaflowne; any number of Emperor Scientists may have this going on as well.
 * Which isn't much of a surprise when you realize Dornkirk is actually.

Comic Books

 * In Watchmen, Dr. Manhattan's ability to make rare elements from scratch is the reason his world has cancer-free cigarettes, efficient zeppelins and cheap electric cars.
 * Lex Luthor in Superman Red Son is responsible for technology decades ahead of its time.
 * In main DC continuity, the city of Metropolis was "upgraded" by Brainiac around New Year's Day 2000 to be centuries ahead of its time.
 * In Elf Quest's "Shards" arc, the half-elf, half-troll Two-Edge becomes this for the human warlord Grohmul Djun.
 * In Universal War One, Kalish finds a way to travel through space and time, and litterally starts a new civilization.

Film

 * Meet the Robinsons has a fairly extreme example: Cornelius Robinson has invented all the cool new stuff we see the future has, and it's managed to become widely adopted by the time he's still middle-aged!
 * Saruman could be seen as the evil version of this trope.

Live Action TV

 * On Stargate Atlantis, McKay does this to/for a civilization he mistakes for a Sim game, bringing them from Medieval Stasis to Steampunk over the course of two years.
 * Which doesn't sit well with his "game" opponent John Sheppard, whose country reflects his military mindset, and who constantly complains that McKay cheated by advancing them too fast.

Literature

 * A Connecticut Yankee in King Arthurs Court, as stated above. Hank develops bicycles, gunpowder, and even electricity, enriching the lives of the medieval peasants.
 * Leo Frankowski's The Cross Time Engineer series.
 * The Prince Roger series has Space Marines crash on a planet chock full of alien barbarians. In order to make it across the planet to the spaceport, they ally with certain tribes and give them Roman Empire-era technology and tactics.
 * Safehold: Nimue "Merlin" Alban brings modern technology back to the colonists, who are in a sort of involuntary Space Amish-ism.
 * Among the locals, Baron Seamount is so this that at least one character argues against telling him about the technology stolen from them in part because he's already single-handedly progressing Safehold technology without access to the knowledge, thus furthering exactly the sort of inquisitive scientific mindset the protagonists want to encourage in Safeholdians generally. If everybody bringing technology back to Safehold is just duplicating stuff that was developed on Old Earth that's not going to encourage the desired mindset.
 * Martin Padway in Lest Darkness Fall invents distilleries, the telegraph, the printing press, the telescope... He's a time traveller stuck in Italy just before Justinian's disastrous reconquest, so he tries to make the best of it.
 * In "The Deadly Mission of Phineas Snodgrass", a Deconstruction of Lest Darkness Fall, a man goes back in time to the Roman Empire and brings them modern knowledge until a thousand years later the Earth is so overpopulated that the future sends someone else back in time to kill him just as he arrives in Roman times. The last line in the story is "And darkness blessedly fell".
 * Subverted in Mostly Harmless: Arthur thought he could do this since he comes from a technologically advanced place (compared to the place he ends up at), but then he realizes he didn't know how any of that stuff actually worked. The one invention he ends up bringing to them is... sandwiches.
 * Also subverted in Poul Anderson's story The Man Who Came Early: A 20th-century American GI teleported back to Viking-era Iceland tries to fast-forward technological progress, but fails utterly.
 * J.F. Bone's novel The Meddlers: A man's starship runs out of fuel (wire made out of precious metals) and he lands on a primitive planet. He must teach the natives how to use technology so he can get enough fuel to get home.
 * Sherkaner Underhill takes technology from WWI-ish to present day singlehandedly in Vernor Vinge's A Deepness in The Sky.
 * A Fire Upon the Deep reveals that every spaceship carries 'uplift' files, in case they get caught in the slow zones where higher end technology won't work, and they have to build lower-tech replacements to get back to the higher zones.
 * In Michael Swanwick's Jack Faust, German scholar Johannes Faust kickstarts a technological revolution that skyhooks Renaissance Europe into the early 20th century in the space of a century. Justifiable in this case, as the story is written more as a fable than a realist novel (at least, if the parts where Mephistopheles tells Faust how to create new technologies is anything to go on).
 * Subverted in the Discworld with Leonard of Quirm, who could create massive technological change had the Patrician not had him placed in a large, airy room for which he has the only key, where his failure to consider the consequences of his inventions can't do any harm. This is a man who created something for use in the mining industry "for when they want to move the mountains out of the way".
 * While not a one person Industrial Revolution, the core cast of Everworld manages to plant the seeds for technology, starting in Enter the Enchanted, where April shows Merlin how to perform a blood transfusion, but more significantly in Discover the Destroyer, where Jalil and David manage to get a lot of gold for showing the fairies how to construct a telegraph. It all comes to a head in the last two books where the technology has spread so drastically that there is now electricity and cable cars. It goes even further when, after battles, April instructs the elves in safety from germs and bacteria, as well as other things. Christopher was of the belief that April's contribution brought the study of medicine in Everworld forward by about five hundred years practically overnight.
 * Not to mention trading the formula for gunpowder (out of a high school chemistry book) to some aliens in exchange for a little upgrade to their pocketknife.
 * The protagonist of R. A. Lafferty's Rainbird is this. So brilliant is he that at the end of his life he invents a time machine so he can give his younger self all his future inventions, allowing young!Rainbird to work on even more advanced technologies.

Tabletop Games

 * GURPS Time Travel supplement Alternate Earths has this. In the "Gernsback" parallel, Nikola Tesla's inventions revolutionized the modern world.

Video Games

 * Arcanum gives us Gilbert Bates, who invented the verse's first steam engine, sparking an industrial revolution that transformed Tarant from a backwater hole into a world superpower.
 * Mordred on the 'Astro-knights' island in Poptropica.
 * Many, many Alternate History stories cast Nikola Tesla as this. For instance, Command and Conquer did it.
 * Red Alert does it with Einstein.
 * Kane. A more generous interpretation of his actions is that he's preparing humans to be able to use Tiberium and deal with the Scrin.
 * In Lufia: Curse of the Sinistrals, Lexis is responsible for technology based on Energy Cores.
 * Lucca in Chrono Trigger, in fact; she lead to  based on her technology in Chrono Cross.
 * The Kappa were already technologically advanced in Touhou, but the Goddess Kanako feeds a dead sun god to a Hell Raven to give them access to nuclear power; and start their Industrial Revolution.
 * Infel from Ar Tonelico 2 is a one-woman Magitek Revolution. Nearly everything about current-age Reyvateils can be traced to her.
 * Jade Curtiss of Tales of the Abyss developed This invention changed the very landscape of the world of Auldrant, and Jade was just a kid!
 * Jade Curtiss of Tales of the Abyss developed This invention changed the very landscape of the world of Auldrant, and Jade was just a kid!

Webcomics

 * Kevyn from Schlock Mercenary might count. He invented the teraport and pretty much changed the whole interstellar ball game: it's amazing how much new tech used and taken for granted in the comic is based off the teraport.

Western Animation

 * The Mechanist of Avatar: The Last Airbender fame can produce tanks, jet skis, and a huge freakin' drill, but the concept of a hot-air balloon eluuuudes him.

Real Life

 * Archimedes almost did this for the Roman empire, but then a soldier went and killed him because he was too busy working on a math problem to respond to the Roman army sacking the city. It could have been something to do with all of the giant death machines Archimedes had built for the Carthaginians, such as a crane for crushing Roman ships. The Greeks at the time had invented a rudimentary mechanical calculator. What Could Have Been...
 * According to some, the Roman soldier was asking him where he could find Archimedes because his boss wanted him alive.
 * In real life, something like an industrial revolution can't be started by a single man, however brilliant. The lack of widespread literacy, educated technicians (who will maintain those steam engines?), advanced banking system and a myriad of other factors would have prevented Archimedes or any other genius from starting a widespread, enduring technical revolution on his own.
 * Infrastructure like that grows organically with technology.
 * Thomas Edison came close in real life. His inventions (or inventions from his lab, anyway) gave birth to electric lighting, the recording industry, the cinema industry, and lots of incremental improvements in telegraphy, power generation, and other fields. He's often a villain in fiction nowadays because of his feud with Tesla, but how can you hate a real-life inventor who actually had a pipe organ in his laboratory?
 * He also inadvertantly gave birth to major film studios based in Hollywood by monopolizing film-making technology, forcing independent film-makers to run as far away they could. Namely, to California.
 * Edison could be an indirect example. Though many inventions attributed to him may actually have been from the various inventors he employed, it was his business methods that enabled those inventions to crystallize in the first place. Quite a few also spread because of his efforts to promote them -- his celebrity status earned the public's trust for new technologies with his name stamped on them.
 * Well, Nikola Tesla is widely credited as the inventor of most of the electrical systems in use today. The guy pioneered AC and perfected its use in the USA, then went on to develop things like radio, remote control, fluorescent lightbulbs and the wireless transmission of electrical power (which we're only now implementing into consumer products). Also, VTOL aircraft and a Death Ray... maybe.