Literally ever other evolutionary stone had gained at least one pokemon that evolved from using them except this one. Generation 5 introduced a new evolution for each pre-existing evolution stone besides the dawn stone and in XY the other gen 4 evolution stones got attached to three-stage lines besides this one. Ironically both are the only gens to not have branching evolutions which seemed to be the dawn stones gimmick alongside gender based evolutions, Even the new ice stone got Cetoddle in SV
There are tons of items that only evolve a single pokemon and then are never used again but it seems like they purposely want to give the other stones new pokemon to evolve in future generations but after almost 20 years they seem to be content with just these two.
by theguyinyourwall