NFE Extreme Evoboost Cleaner (Eevee) @ Eevium Z  
Ability: Adaptability  
EVs: 252 SpA / 4 SpD / 252 Spe  
Modest Nature  
- Last Resort
- Hyper Voice  
- Stored Power  
- Hidden Power [Fire]
Optional Move(s): 
- Shadow Ball
Optional Item(s): 
- N/A
Optional Ability: 
- N/A
Optional EV/IV(s):  
- 252 SpA / 4 SpD / 252 Spe (Timid)
Overview: With access to Eevium Z and Last Resort, Eevee is capable of boosting all stats except Accuracy and Evasion by +2, which makes it a very threatening setup sweeper once boosted. However, its very poor bulk and low speed prior to the boosts limit it to only being able to set up on certain bulky Pokemon like Roselia and Metang. Eevee usually requires heavy team support in the form of dual screens, Memento, or Sticky Web support in order to do its job effectively.
Extreme Evoboost Cleaner: Last Resort turns into Extreme Evoboost when Eevee is holding Eevium Z. Stored Power has 220 Base Power after Extreme Evoboost and either OHKOs or 2HKOs all super effective and neutral targets. Adaptability boosted Hyper Voice hits neutral targets which resist or are immune to Stored Power such as Alolan Grimer and Duosion hard. Hidden Power Fire provides valuable coverage to hit Steel-types such as Metang, Ferroseed, and Pawniard hard and beat them after chip damage.
Checks and Counters: There are Pokemon capable of eating any hit from +2 Eevee and can cripple it, hit it hard, or remove all of its boosts, such as specially defensive Servine, Alolan Grimer, Ferroseed, and Dusclops. Priority users such as Monferno can revenge kill Eevee with Mach Punch after some good chip damage. Even at +2, Eevee is quite slow for a cleaner so faster Choice Scarf users such as Electabuzz, Frogadier, Kadabra, and Torracat can revenge kill +2 Eevee after some chip damage.