The most comprehensive, usable resource summarizing summer funding resources can be found in PSJD’s resource center here. PSJD’s resource contains a long list of paid public interest positions like the Google Policy Fellowship, stipends awarded annually by outside sources such as the Minority Fellowship in Environmental Law (which is awarded by the New York State Bar Association), and fellowships that students can use to work at a wide variety of organizations such as Equal Justice America’s Summer Fellowships. Students, when seeing this list, are often surprised that there are multiple sources of funding they had never thought of.
In addition to those excellent options listed in the PSJD list, many state and local bar associations also have summer funding options available. Further, many law schools receive federal work study funding that students can use over the summer. If your school does not have any federal work study funding for summer positions, it is worth having a conversation with your office of Financial Aid to see if they may consider that option going forward.