Custom
Customary international law (or simply “custom”) is the term used to describe a general and consistent practice followed by States deriving from a sense of legal obligation. Thus, for example, while the Universal Declaration of Human Rights is not in itself a binding treaty, some of its provisions have the character of  customary international law.

Declarations, resolutions etc. adopted by UN organs
General norms of international law principles and practices that most States would agree are often stated in declarations, proclamations, standard rules, guidelines, recommendations and principles. While no binding legal effect on States ensures they nevertheless represent a broad consensus on the part of the international community and, therefore, have a strong and undeniable moral force on the practice of States in their conduct of international relations. The value of such instruments rests on their recognition and acceptance by a large number of States, and, even without binding legal effect, they may be seen as declara- tory of  broadly accepted principles within the international community.