Where can I find a list of all the possible careers/majors to choose from?

Question

I need to consider all of them.

Answer 1

In the school catalog of the university you wish to attend.  Different universities offer different majors.

Answer 2

check your library for The College Board index of majors and graduate degrees. If they don't have it get them to ILL it for you.  If you check at a academic library, it probably will be in the reference area at L901 .C744.  The U.S. Department of Labor has the on-line the Occupational Outlook Handbook, also may be in print at the library.