If you are trying to figure out which awards might fit with your interests, you want to study:
Look into Goldwater, Hertz, Gates Cambridge (specifically for study in England at Cambridge,) or Udall (specifically for environmental sciences).
Look into Boren.
Public service, government and foreign affairs
Look into Truman and Pickering.
Look into Fulbright, Boren, and Gilman (specifically for Pell Grant recipients.)
Study abroad specifically in England
Look into Marshall, Rhodes, or Gates Cambridge (specifically for science.)
Study abroad specifically in Ireland
Look into Mitchell.