Some moves have other effects/bonuses not listed in the Attack Dex. Post any additions that need added to the list and I will update it.
Sunny Day:
Fire-type moves +50%power
Water-type moves -50% power
Lowers accuracy of Thunder to 50%
Solarbeam is made into a one turn move
Changes Weather Ball to a Fire-type move
Castform to its Fire-type form
Ability of Dry Skin - Takes damage every turn
Ability of Chlorophyll - Doubles Speed stat
Ability of Leaf Guard - Unaffected by Status conditions
Ability of Flower Gift - Increase both Att. & Sp. Att 50% for you and ally, Cherrim blooms
Ability of Solar Power - DoT damage to own health, but increases Sp. Att (need %'s)
Rain Dance:
Water-type moves +50% power
Fire-type moves -50% power
Raises accuracy of Thunder to 100%
Lowers power of Solarbeam by 50%
Changes Weather Ball to a Water-type move
Castform to it's Water-type form
Ability of Dry Skin - Gain Hp every turn
Ability of Swift Swim - Doubles Speed stat
Ability of Hydration - Unaffected by Status conditions
Ability of Rain Dish - Recover 1/16th oh total HP at the end of turn
Sandstorm:
Damages Pokémon not of the Rock-, Ground-, or Steel-types every turn
Lowers power of Solarbeam by 50%
Lowers accuracy of Thunder to 50%
Raises the Sp. Def. of all Rock-types by 50%
Changes Weather Ball to a Rock-type move
Ability of Sand Veil - Raises Evasion by 20%
Hail:
Damages Pokémon not of the Ice-type
Raises accuracy of Blizzard to 100%
Changes Weather Ball to an Ice-type move
Castform to its Ice-type form
Ability of Ice Body - Recovers HP during Hail
Ability of Snow Cloak - Raises Evasion by 20%
Earthquake:
Causes 2x Dmg on pokemon using the move Dig
Gust:
Causes 2x Dmg on pokemon using the moves Fly or Bounce.
Sky Uppercut:
Able to hit pokemon using the move Fly.
Gravity:
Ground-type moves will hit Flying-type and pokemon with Levitate. Prevents opponent from using the moves: Fly, Splash, Bounce, and Magnet Rise.(Will disable any of these currently in use as well)
Magnitude:
Causes 2x Dmg on pokemon using the move Dig.
Rollout:
Causes 2x dmg if used after the move Defense Curl.
Sky Attack:
High crit rate.
Stomp:
Causes 2x Dmg if used when the opponent is using Minimize.
Surf:
Causes 2x Dmg on pokemon using the move Dive.
Thunder:
Able to hit pokemon using Fly or Bounce.
Whirlpool:
Causes 2x Dmg on pokemon using the move Dive.