Few items can be utilised for EV training are Exp.Share, Amnesia brace and Macho brace
Exp share- all pokemons with exp share in your party will gain EV and exp until they are maxed, regardless in battle or not
Amnesia brace- pokemon with Amnesia brace must be in battle and gain EV only
Macho brace- pokemon with macho brace must be in battle, gain double EV and exp, but speed is cut havled
I personally don't like Macho brace