Electronic phase separation (EPS) refers to spontaneous phase separation due to competing electronic interactions. It is considered relevant to a number of most spectacular phenomena in condensed matter such as high-temperature superconductivity and colossal magnetoresistance. We probe EPS resulting from delicate interplay of magnetoelectronic interactions in various magnetic materials (e.g., ferromagnetic semimetal EuB6); we particularly look for universal signatures of EPS and the concomitant percolative phase transitions in macroscopic magnetotransport (e,g., the colossal magnetoresistance and unusual nonlinear Hall effect.