Sites about types of investments, that is ...
If you're not sure what an ADR (American Depositary Receipt) is, here's a quick definition from Wikipedia.
These sites offer limited information on companies, usually only products or services, location and contact information. They do not usually distinguish between public and private companies.
In addition to the websites below, be sure to check out the subscription database ESG Manager for SRI screening.
This is not a comprehensive list obviously ...