Alright, here is my signature pokemon team with my signature pokemon, Gassy Dreams(Musharna). I want it to be checked out by fellow competitive battlers. Ones with more experience than I. Constructive criticism only please. Also, this was my early competitive teams, when I started competitive battling XY era. I use this team in OU a lot (use to).
Gassy Dreams (Musharna) (F) @ Leftovers
Ability: Synchronize
Shiny: Yes
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Calm Mind
- Baton Pass
- Stored Power
- Moonlight
Musharna is just straight up my favorite pokemon. Its function is to start setting up Calm Minds and to then use stored power. I have taken Knock Offs from a Conkeldurr, while Musharna was holding leftovers and she survived it. Also that could be easily predicted as you could moonlight the damage off and continue to set up. Now, since Musharna is completely walled by dark types, you could baton pass the stat boosts to another pokemon.
#2FAB4U (Ampharos) (M) @ Ampharosite
Ability: Static
EVs: 16 HP / 240 SpA / 252 Spe
Timid Nature
- Dragon Pulse
- Thunderbolt
- Agility
- Cotton Guard/Toxic
Ampharos's purpose is to be the receiver of the baton passes of Musharna, if she could not sweep any more due being walled by dark types or some other situation. Now, let me tell you something amazing. This specific Mega Ampharos set can outspeed a Timid Greninja with just one agility, even after the base speed drop, goodbye Greninja! If Ampharos receives the baton pass of Musharna, I can throw in a cotton guard if I predict a switch to a pokemon who could take him out on the defensive side. Or you could throw in toxic to toxic a predicted switch. I prefer cotton guard.
Aslan (Arcanine) (M) @ Life Orb
Ability: Intimidate
Shiny: Yes
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Wild Charge
- Flare Blitz
- ExtremeSpeed
- Will-O-Wisp
Arcanine is just the last filler for this team, You could replace it with some other pokemon if you wish to do so. Arcanine is just a physical sweep/potential wall breaker. He deals quite a lot of damage with this set.
Hungry Hippo (Hippowdon) (F) @ Smooth Rock
Ability: Sand Stream
EVs: 252 HP / 252 SpD / 4 Def
Careful Nature
- Stealth Rock
- Earthquake
- Slack Off
- Ice Fang
Hippowdon's purpose is to set up sandstorms, set up stealth rocks, and be a wall. Ice Fang to take out annoying Gliscor in OU, earthquake for stab, slack off to recover lost health.
Bertha (Stoutland) (F) @ Choice Band
Ability: Sand Rush
EVs: 4 HP / 252 Atk / 252 Spe
Adamant Nature
- Play Rough
- Fire Fang
- Return
- Ice Fang
Stoutland here is the secret weapon of this team. This set packs quite a punch. With sand up, Bertha can outspeed most threats and hit them hard before they could hit her. Fire Fang for Ferrothorn, Ice Fang for Landorus, Gliscor, Latios, and any other threat weak to ice; Play Rough for coverage and Return for stab.
*FABULOUS* (Roserade) (F) @ Black Sludge
Ability: Natural Cure
EVs: 252 HP / 252 Def / 4 SpA
Bold Nature
- Spikes/Aromathearpy
- Giga Drain
- Dazzling Gleam
- Hidden Power [Ground] [Fire]
Roserade is a physcial wall that could counter Rotom-W and to set up hazards or to heal status conditions. Roserade can take physical hits very well, except from a flare blitz from a Mega Charizard X. HP Ground to predict a switch in on Heatran or HP Fire to predict a switch in on Ferrothorn. Spikes to cause extra damage on the opponent's team or Aromathearpy to cure status ailments. Giga Drain for stab and recover lost health, Dazzling Gleam for common dragons and fighting types.
P.S. Yes, I have won many battles with this team against OU teams.