Lot of intriguing answers here.
Other less obvious Tech POD's:
Move up alloying of iron with nickel for a big improvement in steel along with increasing the carbon content (or adding tungsten/wolfram, etc.), bizarre it took from the Hittites' iron to late 19th Century top technology hubs to really advance from soft steels to far more useful ones for everything from machine tools to locomotives to lighter engines to dreadnaught's guns. Using diverse metals to get a more useful mix goes back to bronze and brassmaking while many of the key alloys for iron occur randomly and in varying proportions in the natural deposits and meteor iron. Having that noticed and developed at the Great Library of Alexandria, Roman arsenals, Phoenician traders, any major crossroads with a vibrant metalworking industry would be a good possibility. Better steel than the competition in anything from shipbuilding to sewing machines is one of those advantages that compounds rapidly.
Petroleum refining on a sustained, large scale could have happened in the 18th instead of the 19th century, the original technology was that simple and tar pits/oozing pools of oil at the surface had been long noted (using it to waterproof baskets may have been the first commercial use.) Do that and the whaling fleets don't develop so a lot of wealth that went to whaling towns/states doesn't occur which have many ripples in American New England particularly-either extending distant trade routes or heading into the American and Canadian interior looking for wealth (and no "Moby Dick!" as well as some of the shipbuilding lessons from whaling ships.)
Having a much higher energy to mass or weight fuel available might make early railroading instead of later railroading driven by diesel engines or kerosene heated steam engines instead of cordwood, put engines on ships and boats decades earlier, allow much earlier factory automation for small shops than the coal-fired steam boilers driving leather belts on the machinery did...so lots of big ripples there.
Much earlier domestication of camels would have many impacts since they have advantages over horses and donkeys in many parts of the world and likely would have spread much further across Eurasian and African civilizations, making long trade routes viable many centuries or millenia earlier and changing who was mounted and attacking who and where considerably (like using elephants for war did.)