Google, the number 1 search engine in the world has a great repository of data. Google public data explorer is essentially a search engine for data sets published for public use. It aggregates data sets from organizations like World Bank, Eurostat, IMF, ASEAN statistics and more.
You can filter results by indicator type (eg. GDP growth, fertility rate, Gini coefficient) and do country to country comparisons.
2. CIA factbook
CIA factbook provides country to country data sets, highlighting economic, health and population indicators. It gives country specific summaries, which are useful if you want to find information on a specific country or region.
UNdata collates data from countries and regions. It covers economic, social and environmental indicators.
The website provides users access to open data on cancer research data. Researchers can upload their findings to this database commons. Users can view projects and data analysis.
The website provides data on businesses and consumer expenditure. Lots of info graphics which are easy to understand. Free use gives you access to basic data sets. Priced plans grant you access to premium data sets.
Kaggle claims itself to be the home for data science. It holds a repository of data sets that are open access. It creates competitions and discussions for users to upload their data findings. Browse through other data submissions and use them for your data project.
Knoema is a website that provides free data on on various topics like industry, economics and country specific data. Lots of visualizations which you can customize to view data sets. Paid plans give you access to premium content.
They also have a blog which discusses data sets and identifies trends and issues around the world.
Website provides open data on global climate and weather.
Country Specific data websites
Provides data on US. Highlights indicators such as economic, social, health and environmental.
Provides data on Singapore. Reports indicators such as economic, health and social. Lots of info graphics that are easy to understand.