The Brown University Library offers a Library Resource Guide for Grant Resources that includes access to subscription services, such as Pivot, formerly known as the Community of Science (CoS) Funding Opportunities database. These resources are accessible via an on-campus workstation with a Brown NetID and password, or off-campus by logging in through a proxy server. For assistance with off-campus access, contact Computing and Information Services.
Another source is Pathways to Science.
The Open Education Database offers a list of 100+ Places to Find Funding For Your Research.