So, this is a new team I made awhile back. It's so-so I believe. 
AT A GLANCE 
 
So, as you can see, this is a team centered around Mega Diancie. 
THE TEAM 
 
Princess (Diancie-Mega) @ Diancite   
Ability: Clear Body  
EVs: 248 SpA / 8 Atk / 252 Spe  
Naive Nature  
- Protect  
- Moonblast  
- Diamond 
- Hidden Power [Fire]
 
 
So, I always like to have a Mega on my teams and I wanted to try out Mega Diancie.
 
Crooks Key (Klefki) (M) @ Light Clay  
Ability: Prankster  
EVs: 248 HP / 8 SpD / 252 Def  
Impish Nature  
- Thunder Wave  
- Reflect  
- Light Screen  
- Foul Play  
I knew I needed a stealth rock setter, but I thought instead of a stealth rock setter, why not go with Reflect/Light Screen. I also saw many people go with Klefki so I thought of trying it out. So, basically, Klefki is the pokémon I always lead with in order to set up Reflect/Light Screen. Also, if it doesn't faint, I just put Thunder Wave and then try to attack with Play Rough.
 
Excavate (Excadrill) (M) @ Choice Scarf  
Ability: Mold Breaker  
Shiny: Yes  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Earthquake  
- Rapid Spin  
- Iron Head  
- Rock Slide  
 
Even though Excadrill has Rapid Spin, I don't lead with it. Excadrill is my physical attacker in this team. Earthquake + Choice Scarf is really strong. However, it's a bit hard to use Rapid Spin since it has Choice Scarf, so if possible, I would like another item to put on Excadrill if possible.
 
Washington (Rotom-Wash) @ Leftovers  
Ability: Levitate  
EVs: 252 HP / 4 SpA / 252 SpD  
Calm Nature  
- Volt Switch  
- Hydro Pump  
- Will-O-Wisp  
- Pain Split  
 
So, Rotom-Wash, as you have guessed it, is my "switch-in" pokémon. Like, for example, I switch out one of my pokémon to Rotom. Well, anyways, you get the point.
 
Kid (Weavile) (M) @ Life Orb  
Ability: Pressure  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Low Kick  
- Ice Shard  
- Knock Off  
- Icicle Crash  
Weavile is another one of my physical hitters. It has Knock Off so that if the opponent switches, I will the surprise the opponent by knocking off its item.
 
Big Blaze (Talonflame) (M) @ Sharp Beak  
Ability: Gale Wings  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Brave Bird  
- Roost  
- Swords Dance  
- Flare Blitz  
 
Talonflame is the strongest physical hitter here. Swords Dance + Sharp Beak + Brave Bird KOs any pokémon. However, it has recoil and can't take hits, which is why I have Klefki set up Reflect/Light Screen first so that it can take damage. I also have Roost on it so that it can recover from Recoil.
 
Copy-paste Team
 
 
There's my team for you guys. Let me know what you guys thought of this team walkthrough and what I can do to improve it! Also, suggestions for the team are greatly appreciated! 
 
Thanks for tuning in to this team walkthrough!