Throwing my hat into the ring because Wynaut.
Swampert @ Swampertite
Ability: Damp
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Rain Dance
- Waterfall
- Earthquake
- Ice Punch
Cobalion @ Shuca Berry
Ability: Justified
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Stealth Rock
- Volt Switch
- Iron Head
- Close Combat
Togekiss @ Leftovers
Ability: Serene Grace
EVs: 248 HP / 8 Def / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Air Slash
- Roost
- Heal Bell
Starmie @ Life Orb
Ability: Analytic
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Hydro Pump
- Ice Beam
- Thunderbolt
- Rapid Spin
Rotom-Heat @ Choice Scarf
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Volt Switch
- Overheat
- Trick
- Thunderbolt
Kyurem @ Choice Specs
Ability: Pressure
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Ice Beam
- Draco Meteor
- Earth Power
- Hidden Power [Fire]
Ability: Damp
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Rain Dance
- Waterfall
- Earthquake
- Ice Punch
Cobalion @ Shuca Berry
Ability: Justified
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Stealth Rock
- Volt Switch
- Iron Head
- Close Combat
Togekiss @ Leftovers
Ability: Serene Grace
EVs: 248 HP / 8 Def / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Air Slash
- Roost
- Heal Bell
Starmie @ Life Orb
Ability: Analytic
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Hydro Pump
- Ice Beam
- Thunderbolt
- Rapid Spin
Rotom-Heat @ Choice Scarf
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Volt Switch
- Overheat
- Trick
- Thunderbolt
Kyurem @ Choice Specs
Ability: Pressure
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Ice Beam
- Draco Meteor
- Earth Power
- Hidden Power [Fire]
Basically it's an offensive team built around Rain Dance Mega Swampert. Swampert is the main sweeper, easily being able to clean late game thanks to its huge power and massive Speed in rain. Cobaliion sets up Rocks. Togekiss is my stall breaker and cleric, and can easily smash through the bulky Grass types that give Swampert trouble. Starmie keeps entry hazards away, and hits like a truck in rain. Rotom-H is my main revenge killer, and can also check stuff like Xurkitree, Scizor, and Suicune. Kyurem is my main wallbreaker - hits like a truck with Choice Specs, and STAB Ice Beam lets it wreck the Grass types that trouble Swampert.