Note: Eevee has proved itself to be a very good late game sweeper because of it's access to Extreme Evoboost to double it's stats. Last resort is there so that the z-move can actually be used but shouldn't be clicked otherwise. After the boost stored power has an amazing 220 base power which is capable of OHKOing a lot of Pokemon so it should be the main attacking move used. Hyper voice is there to hit the dark types that stored power can't. Substitute is used for bulky Pokemon that won't get OHKO'd so that you can take as little damage as possible so that you don't get beat down by priority. Heal bell is an options to get rid of status and if Eevee doesn't get a chance to set-up it can still help the team.
Checks & Counters: Moves such as haze and roar which can get rid of Eevee's boosts render it pretty much useless as it can only set up once. Hard hitters such as Gurdurr and Kadabra can hit Eevee before it sets up to either kill it or leave it vulnerable to priority moves. Steel types resist both hyper voice and stored power so can take these attacks and fire back but have to be wary of hidden power fire or ground. Specially defensive pokemon like Munchlax and Dusclops can take a stored power and either get off some damage or can status Eevee to wear it down unless heal bell is being ran.
Other Options: Hidden power fire/ground can be used to deal heavy hits to the steel types like Ferroseed and Metang that could take a stored power. Shadow ball is also an option to hit Pokemon like Dusclops and Metang for a lot of damage. A bulkier spread could be ran with 160hp/252spatk/96spe so that you can outspeed Kadabra and Electabuzz at +2 and take hits better to set up easier.
