Sun Offense
Drought Charizard or Torkoal sets the Sun, and Chlorophyll sweepers and Fire attacks run through the field.
The build
Sun Offense pairs a weather setter (Mega Charizard Y or Drought Torkoal) with two Sun abusers (Chlorophyll sweepers or Fire spam). The 1.5x Fire boost + halved Water damage breaks anything that doesn't pack a Rain or Sand counter.
Signature Pokémon
Charizard 
Torkoal 
Leafeon 
Incineroar Lead options
Charizard + Torkoal for double-sun pressure, or Charizard + Incineroar for pivot speed.
Win condition
Get sun up turn 1, Heat Wave / Eruption / Solar Beam everything off the field before your weather expires.
Hard counters
Rain (Pelipper) flips the matchup. Tyranitar Sand overwrites your weather. Specific anti-sun tech: Wide Guard + Heat Wave-resist cores.
Signature moves
Sample team
Plug-and-play 6-Pokémon roster you can import to the team builder. Adjust EVs / nature / move slots based on your specific local meta and tournament reg.
Whimsicott 
Garchomp 
Kingambit