Williamina Fleming didn't discover individual stars in the sense of finding them for the first time. Her work was about classifying and categorizing existing stars based on their spectral characteristics.

However, her work led to several important discoveries and advancements in astronomy, including:

* The discovery of over 10,000 stars. While she didn't "discover" them in the literal sense, she classified and catalogued them, making them accessible for further study.

* The discovery of the first white dwarf star. This discovery challenged the prevailing theories about stellar evolution at the time.

* The development of the Harvard Classification System. This system, still used today, classifies stars based on their spectral types (O, B, A, F, G, K, M).

Fleming's contributions were crucial for understanding the composition, evolution, and properties of stars. While she didn't name specific stars, her work paved the way for countless future astronomical discoveries.