The National Institutes of Health has created two webpages identifying grant funding opportunities and various resources pertaining to COVID-19.
Scroll to the bottom of this first link for funding opportunities:
This second link explains how NIH’s emergency funding works and which Institutes received additional funds:
Where to Find COVID-19 Funding Opportunities
NSF has released a Dear Colleague Letter announcing an opportunity for researchers with active NSF awards to apply for supplemental funding for research visits to collaborate with PIs funded through the European Research Council.
A similar opportunity to collaborate with researchers in Ireland and Northern Ireland may be found here.
In response to many undergraduate summer opportunities having been lost to the pandemic, the CISE directorate has extended its deadline for submitting REU Supplements to July 1st, 2020. Please consult this Dear Colleague Letter for further details.