A plethora of proteins are able to express iron-sulfur clusters, but have a clear picture of the different types of proteins and the different iron -sulfur clusters they harbor it is not easy. In the last five years we have reviewed structure/electrochemistry of metalloproteins expressing: (i) single types of iron-sulfur clusters (namely: {Fe(Cys)(4)}, {[Fe2S2](Cys)(4)}, {[Fe2S2](Cys)(3)(X)} (X = Asp, Arg, His), [Fe2S2] (Cys)(2)(His)(2)}, {[Fe3S4](Cys)(3)}, {[Fe4S4](Cys)(4)} and {[Fe4S4](Cys)(3)(nonthiolate ligand)} cores); (ii) metalloproteins harboring iron-sulfur centres of different nuclearities (namely: [4Fe-4S] and [2Fe-2S], [4Fe-4S] and [3Fe-4S], and [4Fe-4S], [3Fe-4S] and [2Fe-2S] clusters. Our target is now to review structure and electrochemistry of proteins harboring canonical, non-canonical and hybrid iron-sulfur proteins.