Looking at your team composition, I'm kinda assuming you're going for a pivots + sweepers Bulky Offense kind of style, so I'm going to answer based on that assumption.
Zeraora
So... this set is pretty weird. Volt Switch and Knock Off are basically mandatory on any Zeraora set, or you could run a Bulk Up set, which honestly seems maybe better based on the team composition. Here are the sets:
Zeraora @ Heavy-Duty Boots
Ability: Volt Absorb
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Plasma Fists
- Volt Switch
- Knock Off
- Close Combat
Zeraora @ Leftovers / Weakness Policy
Ability: Volt Absorb
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Plasma Fists
- Bulk Up
- Knock Off / Play Rough
- Drain Punch / Close Combat
The last two moves are mostly by preference; Knock Off is generally prefered but Play Rough can hit things like Dragonite harder. Close Combat for power but Drain Punch provides much-needed recovery.
Zarude
Honestly I think Zarude is outclassed by a lot of things right now; how about you try Rillaboom? It can form a nice little VoltTurn core with Zeraora if you decide to run it. I would say run Choice Band, as it is great for Revenge-killing and pivoting which the rest of your team members can benefit from. However, Swords Dance is also good if you really want setup, which this team can lack.
Rillaboom @ Choice Band
Ability: Grassy Surge
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant / Jolly Nature
- Grassy Glide
- Wood Hammer
- U-turn
- Knock Off / Superpower
Knock Off annoys Corviknight while Superpower hits Ferrothorn harder.
Rillaboom @ Life Orb
Ability: Grassy Surge
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant / Jolly Nature
- Grassy Glide
- Swords Dance
- Drain Punch / Superpower
- Knock Off / U-turn
Drain Punch regains health whereas Superpower can threaten Steels better. Knock Off is always good to have but U-turn can also be used to pivot.
Blissey
Your set is pretty good, but I think all Blissey should run Seismic Toss to make it less passive. Try using it in place of Aromatherapy. Toxic can also be replaced by Thunder Wave in order to give more opportunities for teammates.
Terrakion
Terrakion's main niche in OU is being a Swords Dance sweeper or a lead. However, I feel like it doesn't have that big of a role on this team. For this slot, I would recommend a Defogger, of which I think Corviknight is the best for this team. It's an answer to Rillaboom, Landorus-T, Kartana, and many others that can otherwise be a threat to this team and can grab momentum with U-turn. It also works well with Blissey as a SkarmBliss core, recreated.
Corviknight @ Leftovers
Ability: Pressure
EVs: 252 HP / 168 Def / 88 SpD
Relaxed Nature
IVs: 0 Spe
- U-turn
- Roost
- Defog
- Brave Bird / Body Press
The last move depends on whether you want to hit Bisharp and other steels harder, or if you want a STAB move that threatens Grass-types like Rillaboom.
Dragapult
On this composition, you desperately need a Special breaker, so I'm going to make this set a Specs revenge-killer set, which is able to threaten much of the metagame and gain momentum with U-turn.
Dragapult @ Choice Specs
Ability: Infiltrator
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- U-turn
- Shadow Ball
- Draco Meteor
- Fire Blast / Flamethrower
A Fire-move on Pult is great because it threatens Ferrothorn and other Steels; basically choose between accuracy and power.
Wishiwashi
So, this thing is completely outclassed by Swampert as a bulky Flip Turner. It also provides Rocks which is useful. However, Swampert isn't all that good in the metagame right now. Something like Landorus-T might be better. I'll provide sets for both below.
Swampert @ Leftovers
Ability: Damp
EVs: 252 HP / 4 Def / 252 SpD OR 252 HP / 252 Def / 4 SpD
Sassy / Relaxed Nature
IVs: 0 Spe
- Flip Turn
- Stealth Rock
- Toxic / Yawn
- High Horsepower
Swampert acts as a nice slow Flip Turner that can tank hits as well as cripple something with Toxic. Toxic is generally prefered but Yawn can also be used to gain momentum better. High Horsepower over Earthquake due to Rillaboom's Grassy Terrain.
Landorus-Therian @ Leftovers / Rocky Helmet
Ability: Intimidate
EVs: 252 HP / 164 Def / 92 Spe
Impish Nature
- U-turn
- Stealth Rock
- Earthquake
- Toxic
Unfortunately this doesn't get any good Ground moves that aren't Earthquake, so you'll have to just used the Half-power move if Grassy Terrain is up. Toxic is better for this team than Knock Off due to already having multiple Knock Off users.
So, those are my suggestions for this team. Please comment below if you think I missed something or did something wrong. Thanks for reading, and I hope I helped!
