▶ Archives COVID-19 Collection Project
Please keep in mind that it is easier to find information on public companies. Because public companies are required to file reports with the SEC, there is a lot more information out there about them.
You may still find data on private companies, but it is likely to be much more limited.
Carnegie Library of Pittsburgh has a lot of great business databases. Remote access simply requires that you enter your library barcode. Select "Business" in the Subject dropdown menu and click "Find" to view the full list. Those must useful are:
Company Website - company websites often have a wealth of useful information