I'm dong this on the fly, but here aresome changs that will most certainly improve your Rain team. Changes will be in bold.
Politoed@ Sitrus Berry
Bold | Drizzle
252 HP / 140 Def / 76 SpA / 36 SpD / 4 Spe
- Scald
- Icy Wind
- Helping Hand
- Protect
Sitrus is better than Damp Rock because it lets you survive opposing Pokémon's attacks better. Poli will likely be a priority threat because the opposition will want to cut off your team's support ASAP, and the extra HP can go a long way. Ice Beam over Icy Wind to let you nail Landorus and Salamence.
Thundurus@ Expert Belt
Timid | Prankster
4 HP / 252 SpA / 252 Spe
- Thunderbolt
- Hidden Power [Ice]
- Thunder Wave
- Protect
Expert Belt over Life Orb because the next team member needs it more. Thunder is a poor move, since it becomes completely unreliable outside of Rain. Thunderbolt is much better and more consistent. Focus Blast is also awful in Doubles, where missing an attack can often cost you the game. One of the main purposes of offensive Thundurus is to get some crucial OHKOs with HP Ice, which is why all but pure support Thundy carry it.
Virizion@ Life Orb
Jolly | Justified
4 HP / 252 Spa / 252 Spe
- Close Combat
- Leaf Blade
- Stone Edge
- Protect
Scizor is okay for Rain, but not particularely for this team. Virizion helps you check Charizard Y, a major threat to Rain teams, with Stone Edge. Your team also struggles a bit with bulky Waters like Lapras, Jellicent, and Rotom, which Virizion's Leaf Blade counters nicely. Close Combat checks Ferrothorn, a huge weakness in this team, Kangaskhan, Terrakion, Hydreigon, and Heatran. Protect needs no introduction. Virizion also gives you a Spore and Rage Powder immunity.
Gengar@ Focus Sash
Timid | Levitate
4 Hp / 252 Spa / 252 Spe
- Sludge Bomb
- Will-o-Wisp
- Protect
- Shadow Ball / Trick Room
Toxicroak isn't seen at all in VGC because of its frailty, weakness to Burns / Intimidate, and the fact that many other Pokémon do its job better. Gengar is a good Fairy check with Sludge Bomb, and also helps your team against Trick Room setters, which I'll discuss later. Gengar outspeeds and 2HKOs most Fairies and Grass-types with Sludge Bomb, and almost guarantees it with Focus Sash. Will-o-Wisp improves the teams general bulk as well as crippling threats like Kang and Landorus. Protect is Protect. Finally, based on your prediction skills, you could use Shadow Ball to check Trick Room setters like Chandelure, Cresselia, and Jellicent, or you can reverse their Trick Room with your own, letting you gain back the upper hand.
Gardevoir@ Choice Scarf
Modest | Telepathy
4 Def / 252 SpA / 252 Spe
- Moonblast
- Psychic
- Shadow Ball
- Hidden Power [Fire]
Not much to change here, only HP Fire over HP Ground to nail Ferrothorn, Escavalier and Scizor.
Swampert@ Swampertite
Adamant | Damp
108 HP / 208 Atk / 148 Spe
- Waterfall
- Earthquake
- Ice Punch
- Protect
Swampert's awesome, bruh. I would suggest having Damp as a pre-Mega ability to save you from the occasional Exploding Landorus or Glalie.
Alternatively, you could try using Scarfed Hydreigon over Gardevoir. It helps trim down your Ghost weakness, as well as offering decent Fire coverage against Ferrothorn. Hydreaigon is also still immune to Swampert's Earthquake.
Hydreigon@ Choice Scarf
Timid | Levitate
4 Hp / 252 SpA / 252 Spe
- Draco Meteor
- Dark Pulse
- Earth Power
- Fire Blast / Flamethrower
I like this team! It has a good foundation and synergy. I hope that these changes are able to improve your game. I would suggest watching out for stuff like Will-o-Wisps and Intimidates, as Swampert is severely crippled by them. Good luck!
