ProCon is a non-profit website that presents free, unbiased, and sourced information (with citations!) on many controversial issues along with videos and links to other resources. Any information that presents a point-of-view or opinion rather than fact is clearly labeled for the position (pro or con) that it presents.
Public Agenda is a non-partisan organization that researches and presents information on a variety of controversial issues, including immigration, foreign policy, race, voting, education, energy and climate change, healthcare, and national debt/spending. Try searching the library for information in your issue.
The Pew Research Center is a nonpartisan American think tank based in Washington, D.C., that provides information on social issues, public opinion, and demographic trends shaping the United States and the world. It conducts public opinion polling, demographic research, media content analysis, and other empirical social science research. It does not take positions or present opinions.