Here’s a list to ponder:
Realists, neorealists, globalists, pluralists, neoliberal institutionalists, critical theorists, [C]ritical [T]heorists, structuralists, post-structuralists, modernists, post-modernists, Marxists, post-Marxists, feminists, post-feminists, interpretivists, humanists, thin-constructivists, thick-constructivists, positivists, post-positivists and so on*
The list (from the late 90s) is supposed to illustrate the remarkable pluralism and great diversity of International Relations theory.
But look a bit more closely and what it lists is mainly the many variations on the theme of the standard left-liberal academic perspective.
Notably absent, for instance, are evo/bio/geno/Darwinian approaches or the classical approach.
Has pluralism become an ideology disguising a shortage of real pluralism?
*Colin Wight, Incommensurability and Cross-Paradigm Communication in International Relations Theory: ‘What’s the Frequency Kenneth? Millennium – Journal of International Studies June 1996 vol. 25 no. 2 291-319 p. 297. (pdf)
(h/t Duck of Minerva)