Endotronics's rhymes with:
ionics's, ionics's, phoenix's, affixes, appendixes, dynamics's, essex's, felix's, ionics's, isomedix's, matrix's, matrixes, phoenix's
Endotronics's sounds like:
endearing, endothermic, endotronics, endotronics', endurance, enduring, entering, entrance, entrances, entrench, entrenches