Rejuvenation Crest Effects

Ariados - Increases Speed by 50%, guarantees Critical hits against Poisoned and Slowed Targets
Bastiodon - Deals 50% of the damage it takes as recoil to the Attacker, and Heals for the amount of damage dealt this way
Beheeyem - Reduces Damage Taken from Pokemon Moving before it by 33%,
           Disables Moves that hit it, if attacker doesn't already have a disabled move (cursed Body With 100% activation chance)
Castform - Castform automatically uses it's first weather move upon Switch in, Gives it's weather Form higher Base Stats and an
           Ability:
           Rain: 100 HP / 70 Atk / 80 Def / 70 SpA / 80 SpD / 70 Spe & Rain Dish
           Sun:  70 HP / 70 Atk / 70 Def / 90 SpA / 70 SpD / 100 Spe & Solar Power
           Hail: 70 HP / 70 Atk / 70 Def / 100 SpA / 70 SpD / 90 Spe & Slush Rush
Cherrim - Forces Cherrim into Sunshine Form regardless of weather (activates Flower Gift)
Claydol - Uses Defense as Sp. Atk, Boosts damage of Beam moves by 50%, Solar Beam & Hyper Beam only take 1 turn to use
Cofagrigus - Increases Sp. Atk and Sp. Def by 25%
Darmanitan - Forces Darmanitan to stay in Zen Mode (only works if current Ability is Zen Mode)
Dedenne - Uses Speed as Attack
Dusknoir - Increases Atk by 20% and boosts weaker moves (like Technician)
Empoleon - Stat Changes are Doubled (like Simple)
Fearow - Increases Fearow's Critical Hit ratio by 3 Stages (guaranteed Crits) against targets below 75% Health
Feraligatr - First move after switch in has priority, boosts biting Move damage by 20%
Glaceon - Glaceon Resists Rock and Fighting Attacks
Hypno - Increases Hypno's Sp. Atk and Accuracy by 50%
Infernape - Swaps it's Defense with it's Attack and it's Sp. Def with it's Sp. Attack
Leafeon - Leafeon Resists Fire and Flying Attacks
Ledian - Punching Moves hit 4 Times, Secondary effects only activate on the first 2 hits
Magcargo - Increases Magcargo's Sp. Atk by 10% and Swaps it's Defense and Speed Stats
Meganium - Reduces Damage taken by Meganium and its ally by 20%, Meganium and its ally heal 1/16 of their HP at the end of Turn
Oricorio - Increases Oricorio's Sp. Atk and Speed by 25%
Rampardos - Once per Battle: Rampardos Survives at 1 HP regardless of it's HP before taking damage
Relicanth - Increases Relicanths Attack by 20% and it's Sp. Def by 30%
Seviper - Increases Speed by 50% and Raises Damage depending on how much HP the Target has ( 50% damage boost at 100% Health)
Silvally - Increases current Type's Damage by 50% and gives an Ability based on Silvally's current Type (Doesn't need to be Held)
           Normal: Scrappy ;  Fire: Moxie ; Fighting: Defiant ; Water: Marvel Scale
           Flying: Gale Wings ; Grass: Flower Veil ; Poison: Regenerator ; Electric: Motor Drive
           Ground: Sheer Force ; Psychic: Magic Bounce ; Rock: Solid Rock ; Ice: Thick Fat
           Bug: Tinted Lens ; Dragon: Multiscale ; Ghost: Mummy ; Dark: Strong Jaws
           Steel: Heatproof ; Fairy: Unaware
Skuntank - Raises Attack if hit by a ground move instead of taking damage (Basically Ground type sap sipper)
Spiritomb - Increases Damage Dealt by 30%*the number of Fainted Allies & Heals 1/16 of Max Hp for each Fainted Foe at the end of turn
Stantler - Increases Stantlers Attack and Accuracy by 50%
Torterra - Swaps it's Weaknesses and Resistances (Torterra becomes weak to Ground and Rock, but resists Fire, Bug, Flying & Ice)
Typhlosion - Uses Sp. Atk As Attack, Contact moves deal a second hit with 20% of the damage of the first hit (like parental Bond)
Whiscash - Raises Attack if hit by a Grass move instead of taking damage  (sap sipper)
Zangoose - Poisons Zangoose and restores HP if the User is poisoned (Poison Heal)