The primary purpose of the ISS is to provide an international laboratory to conduct experiments in the weightless environment of microgravity. Tertiary to that is to conduct experiments that do not depend on weightlessness but do require the space environment, such as the Alpha Magnetic Spectrometer ().
There have been about 1000 significant payload science experiments conducted on the ISS. Innovations from these can be hard to track, because they are usually not immediate and usually come from other parties than the original payload investigator.
A payload investigator does an experiment, makes an observation and reports the results, and somewhere an engineer is inspired to apply those results to a practical use. NASA is often not involved in what happens to the experiment data, once it is returned to the investigator on the ground. NASA does try to compile information about some of these benefits via their Spinoff website/journal:
These experiments range from observation of how spiders behave in the absence of gravitational acceleration, to plasma physics to drug cultivation to crystal growth and metallurgy experiments. I read a paper recently about a crystal experiment on ISS that taught scientists a new way to compose a metal alloy that should result in lighter and stronger structures for buildings and airframes.
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Most of these experiments are conducted at the behest of academia and industry. From NASA’s perspective, the ISS is also a laboratory to prepare us for the next level of space exploration and the long duration exposure to space that comes with that. The crew are experiments. Flight surgeons study how space affects the crew members and we adjust our protocols based on the results.
One of the outcomes of this is that we have a much greater understanding of how to ameliorate many of the negative consequences of long duration microgravity exposure. We have refined the exercise and nutrition regimes to the point where we have actually had a few astronauts return to Earth as strong as when they left.