At the moment, PathwaysToScience.org has over 65 portable scholarships and fellowships posted on the site, all with an emphasis on STEM.
Undergraduate scholarships and resources for applying: Summer Research Programs & Scholarships in STEM (Undergrad level) (pathwaystoscience.org)
Graduate fellowships and resources for applying: https://pathwaystoscience.org/Grad.aspx
A quick video tutorial on using our advanced search functions to find funding opportunities: https://www.youtube.com/watch?v=FxKsAGk8dAw&t=16s