In this work we are interested in standard and less standard structured linear systems coming from applications in various fields of computational mathematics and often modeled by integral and/or differential equations.Starting from classical Toeplitz and Circulant structures,we consider some extensions as g-Toeplitz and g-Circulants matrices appearing in several contexts in numerical analysis and applications.Then we consider special matrices arising from collocation methods for differential equations:also in this case, under suitable assumptions we observe a Toeplitz structure.More in...