NFE SpDef Defog (Vibrava) @ Eviolite  
Ability: Levitate  
EVs: 248 HP / 8 Atk / 252 SpD  
Careful Nature  
- Defog  
- Roost  
- Earthquake  
- U-turn  
Optional Move(s): 
- Tailwind
- Toxic
Optional Item(s): 
- N/A
Optional Ability:  
- N/A
Optional EV/IV(s): 
- 248 HP / 252 Def / 8 SpD (Impish)
Overview: Vibrava makes for a unique Defog user, being immune to Spikes and Toxic Spikes, and only taking neutral damage from Stealth Rock. Its solid defensive typing and reliable recovery lets it switch into Roselia, the premier Spiker of the tier. However, Vibrava is quite passive and has a poor matchup against most hazard setters in the tier. It also competes heavily with Vullaby for a teamslot, since Vullaby also has a good matchup vs Spike setters in the tier.
SpDef Defog: This spread allows Vibrava to reliably check common special attackers such as Electabuzz and Magmar, whilst also being able to switch into Roselia. Defog lets Vibrava remove hazards from the field. Roost gives Vibrava much needed recovery, which lets it check special threats better and gives it more opportunities to clear hazards. Earthquake is a good STAB attack which hits Fire-, Poison-, and Steel-types such as Monferno, Alolan Grimer, Combusken, Metang, Magmar, and Klang hard and also chips most neutral targets well even without Attack investment. U-turn lets Vibrava function as a slow pivot, allowing for frailer teammates to be brought in more safely. 
Checks and Counters: Setup sweepers such as Clefairy and Servine can take advantage of Vibrava's passive nature to set up. Strong physical attackers such as Machoke and Fraxure can easily overwhelm Vibrava due to its mediocre defenses. Pokemon carrying Ice-type coverage such as Frogadier and Marshtomp are able to OHKO Vibrava. Vibrava is also unable to deal with Pokemon which have a Ground-type immunity such as Haunter, Misdreavus, and Staravia. Bulky Pokemon such as Marshtomp and Quilladin can easily switch into any of Vibrava's attacks, although they dislike switching into the occasional Toxic. 
Optional EV/IV(s): An alternative spread of 248 HP / 252 Def / 8 SpD with an Impish nature lets Vibrava check physical threats such as Monferno, Combusken, Metang, and Pawniard better at the cost of being more susceptible to attacks from special threats.