...
Talk with your colleagues, where are they submitting proposals?
Review funding sources in the acknowledgement sections of key papers related to your work.
Attend regional and national meetings. Posters and talks list funding sources, and national meetings often have agency representatives that can help.
Search our grants database at GrantForward. (create an account using your SPU username)
Search federal opportunities at Simpler.Grants.gov.
Know of another resource? Let us know and we will add it here.