Our group develops new computational tools of interest for many-body problems in Solid State Physics. We focus on the theoretical study of low-energy electron excitations (electron-phonon interaction, superconductivity, impurities, etc.) and their influence on properties such as transport of charge and spin. We have ten-year experience in the development of tools based on Wannier functions for the efficient calculation of electron-phonon matrix elements. An outstanding recent contribution of our group is a new theoretical framework based on Fermi Surface Harmonics (FSH). This revolutionary methodology has the potential to reduce by several orders of magnitude the computational demand of various problems in Condensed Matter Physics. We are currently making the FSH technique known in the community by its application to a number of problems: spin and charge transport on surfaces as well as in the bulk, electron-state renormalization and electron-phonon theory, superconductivity, magnetic impurities and scattering problems, magnetic anisotropy, non-perturbative methods, etc.