I'd like to expand on one source in an answer offered above: The Collection of Really Great, Interesting, Situated Datasets, or simply CORGIS.
From their About page:
The CORGIS project aims to transform early computer science projects
by introducing real-world data via simple-to-use client libraries.
Data Science offers an authentic context for your students to solve
real-world problems with programming. The CORGIS project has over 40
libraries for subjects such as politics, education, literature,
construction, and more!
CORGIS offers full support for Java, Python, and Racket, in addition
to making its data files available in common data formats like JSON
and CSV. Some datasets are also available through our unique
Visualizer platform, which enables data science exploration directly
within the browser!
The topics available for analysis are incredibly wide-ranging (as exemplified in the list above). I plan on showing this to my students next year for the AP CS Principles Create Task. My students are comfortable by that point with Python, so this is right at their ability level and will allow for some interesting, innovating, and original project ideas. The accessibility level is just right a student finishing the first year of a high school level CS course.