CQ Researcher makes comprehensive reports on many controversial topics.
You can move around the CQ Researcher website by clicking "Browse CQR," then picking a topic from a list:
You can also use the search box at the top.
Points of View Reference Center covers controversial subjects.
In it, you will see a search bar and a list of controversial subjects grouped by category. Just glancing at this list can help you pick a topic. For example, in the screenshot below I see "drilling in the Arctic" as a topic:
Click on a topic for more information. This shows an overview of the subject (indicated by 1 in the screenshot below) as well as links to further sources of information (2 in the screenshot below):