G Visas: What Organizations in the U.S. Sponsor a G4 Visa for Work

I am currently finishing my master's program in the US on a J1 visa (Fulbright Scholar). Because of family reasons I want to extend my stay here by working for an organization that provides a G4 visa. From what I know international non-profits like the UN and World Bank can provide this visa but are there other organizations that can sponsor G4 work visas for international students?

G Visas: What Organizations in the U.S. Sponsor a G4 Visa for Work