In philosophy, praxeology or praxiology (/ˌpræksiˈɒlədʒi/; from Ancient Greek πρᾶξις (praxis) 'deed, action', and -λογία (-logia) 'study of') is the theory of human action, based on the notion that humans engage in purposeful behavior, contrary to reflexive behavior and other unintentional behavior.

French social philosopher Alfred Espinas gave the term its modern meaning, and praxeology was developed independently by two principal groups: the Austrian school, led by Ludwig von Mises, and the Polish school, led by Tadeusz Kotarbiński.
What is the name of the major school of praxiology not developed by Ludwig von Mises
The major school of praxiology not developed by Ludwig von Mises is the Polish school, which was led by Tadeusz Kotarbiński.