United Nations My World survey - MY World is a United Nations international survey which began in 2015 and is continuously updated. The MY World survey provides insight into attitudes regarding sustainability practices and initiatives divided into many different demographic segments. See also the European Commission Citizens' Views on Development, Cooperation and Aid.
Does your neighbour know about the Sustainable Development Goals? - This blogpost by the Organisation for Economic Co-operation and Development summarizes (and provides links to) several studies that examine attitudes and awareness of SDGs
ICPSR Environmental Attitudes (subject term search) - Provides a lot of data and reports regarding an extremely wide range of subjects.
The Environmental Treaties and Resources Indicators Database - Contains comprehensive information regarding country participation in multilateral environmental agreements.
European Union Environmental Laws and Regulations - Laws, regulations, studies, and other info regarding a wide range of subjects.
United States Environmental Protection Agency (EPA) Laws and Regulations - Provides information and access pertaining to environmental regulations and legislation.
United States Energy Information Administration (EIA) - The EIA is the statistical and analytical agency within the DOE. The EIA collects, analyzes, and disseminates independent and impartial energy information to promote policymaking and public understanding of energy.
Earth Resources Observation and Science (EROS) Center (USGS) - Home to the world's largest collection of remotely sensed images of the Earth’s land surface and the primary source of Landsat satellite images and data products.
Environmental Protection Agency (EPA) Pollution Map - Allows for the searching and downloading of U.S. pollution data.
The Ocean Observatories Initiative Data Portal - Provides real time data so numerous ocean arrays.
Global Fishing Watch Realtime Fishing Maps - Monitors the global commercial fishing fleet, offering near real-time tracking of fishing activity via our public map.
USGS Map Collection - Geologic and topographic maps, 3-D frameworks, geospatial baselines and more.
USGA Water Data - Provides data and water maps over the United States.
Data.gov - The U.S. Governments' open data multidisciplinary repository which provides a wide array of information on sustainability, pollution, environmental policy, and much more.
Dryad - A popular repository which hosts a mix of scientific and medical data.
Figshare - A popular multidisciplinary repository that was created to promote the sharing of scientific data.
Inter-university Consortium for Political and Social Research (ICPSR) - Provides a lot of data and reports regarding an extremely wide range of subjects.