International Grievance Mechanisms and International Law & Governance Project, this research is funded by the European Research Council looks at the different accountability mechanisms of international development financiers: http://www.igms-project.org/
SOMO: The Centre for Research on Multinational Corporations (SOMO) is a not-for profit working on the accountability mechanisms of international development financiers, with excellent publications and resources: https://www.somo.nl/
Accountability Counsel: This non-government organisation seeks to assist communities address grievances and makes policy recommendations to international development financiers: https://www.accountabilitycounsel.org/