Ability: Soul Boost. If the users ally were to faint they would be entirely revived but have half speed (Yes op but the existing eeveelutions get passives that make them op.
Flareon Volacanic: The user is burned but all damage dealing moves deal triple {This is to combat the half attack from burn}
Vaporeon: Slippery: +2 evasion in the rain and gains 1/8 max hp in the rain
Jolteon: Speed Force: The faster you are the more damage you deal)
Espeon: Spirit Cleanse: Restores 1/3 max hp if the opposing Pokemon is KO'd
Umbreon: Shadow Materialization (Summons a Nightime Veil upon entering battle)
Leafeon: Moss: Grassy Terrain+Grass Pelt
Glaceon: Powdered Snow: Snow Warning+Slush Rush
Sylveon: Critical: All moves under 80 base power deal critical hits.{I Ran out of ideas with what to do for slyveon because Pixilate is already so good compared to the rest of the eeveelutions so if anyone has a better idea let me know!!!}
Passive:Illuminate: The User takes only 50% damage to dark type and ghost moves
Ability: Overseer: The user gets a Omniboost every time ANY Pokemon uses a move even if it fails (including itself) and one at the end of each turn along with doubling its partners stats. If the user faints it goes into its second stage form which applies the logic of huge power to all of its stats and heals 1/8th max hp each turn and allows it to use 2 moves in the same turn and +8 Priority.
Passive: Victory: All moves are null accurate (Like Swift and Arial Ace), hit twice, and ignore abilities AND PASSIVES and the user has a 50% chance to live a move that would KO them.