  We survey the applications of universal entropy relations in black holes with
multi-horizons. In sharp distinction to conventional entropy product, the
entropy relationship here not only improve our understanding of black hole
entropy but was introduced as an elegant technique trick for handling various
entropy bounds and sum. Despite the primarily technique role, entropy relations
have provided considerable insight into several different types of gravity,
including massive gravity, Einstein-Dilaton gravity and Horava-Lifshitz
gravity. We present and discuss the results for each one.
