Check out these abundant sources of free and open data.

 
WWF
WWF
US Census Data
US Census Data
Quandl
Quandl
DataHub
DataHub
R3Data.org
R3Data.org
Exversion
Exversion
Federal Reserve Economic Data
Federal Reserve Economic Data
KDnuggets Listing
KDnuggets Listing
Quora Large Dataset Listing
Quora Large Dataset Listing
Google Ngram
Google Ngram
Knoema
Knoema
Shop ethical
Shop ethical
Corporate Critic
Corporate Critic
National Renewable Energy Lab Data
National Renewable Energy Lab Data
World Values Survey
World Values Survey
Data.gov
Data.gov
NASA’s Data Portal
NASA’s Data Portal
Linked Data
Linked Data
Figure Eight (fka; CrowdFlower)
Figure Eight (fka; CrowdFlower)
Social Network Analysis Interactive Dataset Library
Social Network Analysis Interactive Dataset Library
Stanford Large Network Dataset Collection
Stanford Large Network Dataset Collection
Reddit Datasets Feed
Reddit Datasets Feed
 

 

Also, check out this AMAZING list on Github.

You can get information on more great free offerings for doing data science in my book, Data Science for Dummies.