Here are two resources which focus on collecting grant and other funding opportunities in one space:
Here are several subject-specific databases that can be useful for nonprofit research. If your organization serves the LGBT community, then try delving into LGBT Life with Full Text. If you are working on a grant for a domestic violence service group, you might want to look in SocINDEX with Full Text for articles on the issue that include data or information you could use in your proposal. Other library links available through the Subject Lists will help you think creatively about which resources to explore.