ekwb or xspc have many water blocks. it depends on your partiular model. i dont have full knowledge of evga models but i believe the sc2 and lower tier models are using the stock oem pcb and the ftw and higher tier models are using custom pcbs. you kinda need to know what pcb your card has to know which blocks will fit.
that said, if you are just looking for aesthetics a block is nice. if you are looking for performance you should just upgrade to a better gpu.