If you’re looking for sources of public data tucked into web sites, then check out Awesome Public Datasets on GitHub. Organized into categories, the list contains data curated from blogs and user input. Categories include Climate+Weather, education, GIS, government, museums, natural language, time series, and transportation.
Users can contribute entries to the list here.
Visit: Awesome Public Datasets
If the list isn’t GIS-centric enough for you, try taking a look at Robin Wilson’s entry of over 300 GIS data sets. A researcher at the University of Southampton, Wilson has curated the list with sources of free GIS data found over years of research. Datasets are listed by subject type and there is a separate section for country and region specific GIS data.
Visit: Free GIS Datasets
Open data portals are also a great way to locate free or public data. OpenDataSoft has an impressive map containing over 2,800 data portals. These data portals have been geocoded to the map based on the physical location of the portal’s organization. The database containing the entries has been made available to the public domain so you can download the data in a variety of file formats.