OpenIntro features a number of free books that can be used in high school and AP statistics courses. The license on these datasets is currently unknown. You can find out more about OpenIntro at https://www.openintro.org.
Age at first marriage of 5,534 US women who responded to the National Surveyof Family Growth (NSFG) conducted by the CDC in the 2006 and 2010 cycle.
Picostat is a web-based opensource statistical application framework based on Drupal 8 and ℝ. Drupal can be used to manage user datasets and perform basic statistical analysis with a NoCode end-user interface ideal for non-technical users. Custom applications can be easily integrated into the system using webforms and ℝ language syntax.