Hey all!
I haven't played Pokemon competitively in over 4 years, and I just recently got back into it thanks to the new battle sim. Here's my crack at an offensive rain dance team.
Politoed @ leftovers
Drizzle
200 HP/56 Def/252 SpA
Modest
-Surf
-HP Grass
-Ice Beam
-Perish Song
Politoed is a staple on rain teams, pretty generic build, decided to go a bit more offensive since a modest rain boosted surf does a pretty good amount of damage. Perish Song is there to combat any baton pass chains and as a way to finish off the opponent's last pokemon. I usually don't have any trouble with opposing weather inducers, as Politoed hits all of them super effectively. I considered a more defensive ev spread/nature, but Politoed doesn't seem to die too easily, and I always have Tornadus as a backup weather inducer.
Tornadus-T @life orb
Regenerator
4 Def/252 SpA/252 Spe
Naive
-Hurricane
-U-turn
-Superpower
-Rain Dance
Tornadus is an absolute animal in the rain with 100% accurate stab hurricane. I run superpower over focus blast because I hate the miss chance, and it allows me to beat up specially defensive Heatran and Chansey/Blissey more easily. Rain dance is a filler, and useful in case Politoed goes down in a weather war. With a blazing fast speed that outspeeds almost everything non-boosted in OU, Hurricane and U-turn are invaluable. U-turn allows for amazingly easy switches, and the life orb + Regenerator combo makes Tornadus a very hard hitter that is hard to take down.
Ferrothorn @Leftovers
Iron Barbs
224 HP/32 Def/252 SpD
0 speed IV
Sassy
-Spikes
-Stealth Rock
-Power Whip
-Gyro Ball
Ferrothorn is great for entry hazards and as a rock/electric resist, which most of my team is weak to. The double entry hazard allows me to set up easily versus defensive teams, and I didn't find much use with leech seed on an offensive team. I'm pretty good with prediction, and people often try to switch in an Espon or another fast pokemon like Latios, and a gyro ball puts a huge dent into them. I went specially defensive becuase I'm more afraid of strong electric moves (which are almost always special.) However, outrages do tend to be a problem, so I may end up going physical.
Azumarill @Choice Band
Huge Power
252 HP/252 Atk/ 4 Spe
Adamant
-Aqua Jet
-Super Power
-Ice Punch
-Waterfall
I simply love using Azumarill. I can't count the amount of times having a double stab'd priority move coming off of 600+ attack has won me matches. Azumarill punches holes in everything in the rain, even tanks like Skarmory. Azumarill is also surprisingly bulky, and he is a good glue piece on my team. The only problems I have when I use Azumarill is Jellicent and Vaporeon. Ice Punch gives great coverage against many water absorbers (Dragonite, Celebi, etc.) and Super Power absolutely destroys Chansey and Blissey.
Starmie @Life Orb
Natural Cure
4 Def/252 SpA/252 Spe
Timid
-Hydro Pump
-Ice Beam
-Thunder
-Rapid Spin
Starmie does a surprising amount of damage coming from a base 100 SpA. Hydro Pump smashes through even things that resist it, and Bolt/Beam coverage is priceless. I do feel like this Starmie is too squishy and often dies very quickly, so I might switch out spin or Bolt/Beam for recover. I needed a spinner on my team since I use both genies very often. Starmie also pulls its own sweeps with its good speed and SpA.
Thundurus-T @Choice Scarf
Volt Absorb
4 Def/252 SpA/252 Spe
Timid
-Thunder
-Volt Switch
-HP Ice
-Focus Blast
I figured I would put in a strong abuser of Thunder since it's a rain team. Volt Switch is extremely useful, but it can be hard to use given all the ground types running around. Thundurus also goes down pretty quickly especially if there are rocks on the field or a sandstorm is raging. I often lead with an HP Ice just so Gliscor and the like don't get a free switch-in. It's nice to have a fast revenge killer, but Thundurus hasn't been absolutely amazing for me. I also put it in because I figured I needed more electric resists on the team. I'd definitely be willing to switch this thing out for a specially defensive Latias or something else.
Other options I've considered using for this team include:
choice scarf Terrakion
calm mind Keldeo
specially defensive Jirachi
specially defensive Latias
trickscarf Lati@s
Dragonite
Dugtrio
CB Scizor
Thanks a lot for any tips and checking out my rain team! Cheers
I haven't played Pokemon competitively in over 4 years, and I just recently got back into it thanks to the new battle sim. Here's my crack at an offensive rain dance team.

Politoed @ leftovers
Drizzle
200 HP/56 Def/252 SpA
Modest
-Surf
-HP Grass
-Ice Beam
-Perish Song
Politoed is a staple on rain teams, pretty generic build, decided to go a bit more offensive since a modest rain boosted surf does a pretty good amount of damage. Perish Song is there to combat any baton pass chains and as a way to finish off the opponent's last pokemon. I usually don't have any trouble with opposing weather inducers, as Politoed hits all of them super effectively. I considered a more defensive ev spread/nature, but Politoed doesn't seem to die too easily, and I always have Tornadus as a backup weather inducer.

Tornadus-T @life orb
Regenerator
4 Def/252 SpA/252 Spe
Naive
-Hurricane
-U-turn
-Superpower
-Rain Dance
Tornadus is an absolute animal in the rain with 100% accurate stab hurricane. I run superpower over focus blast because I hate the miss chance, and it allows me to beat up specially defensive Heatran and Chansey/Blissey more easily. Rain dance is a filler, and useful in case Politoed goes down in a weather war. With a blazing fast speed that outspeeds almost everything non-boosted in OU, Hurricane and U-turn are invaluable. U-turn allows for amazingly easy switches, and the life orb + Regenerator combo makes Tornadus a very hard hitter that is hard to take down.

Ferrothorn @Leftovers
Iron Barbs
224 HP/32 Def/252 SpD
0 speed IV
Sassy
-Spikes
-Stealth Rock
-Power Whip
-Gyro Ball
Ferrothorn is great for entry hazards and as a rock/electric resist, which most of my team is weak to. The double entry hazard allows me to set up easily versus defensive teams, and I didn't find much use with leech seed on an offensive team. I'm pretty good with prediction, and people often try to switch in an Espon or another fast pokemon like Latios, and a gyro ball puts a huge dent into them. I went specially defensive becuase I'm more afraid of strong electric moves (which are almost always special.) However, outrages do tend to be a problem, so I may end up going physical.

Azumarill @Choice Band
Huge Power
252 HP/252 Atk/ 4 Spe
Adamant
-Aqua Jet
-Super Power
-Ice Punch
-Waterfall
I simply love using Azumarill. I can't count the amount of times having a double stab'd priority move coming off of 600+ attack has won me matches. Azumarill punches holes in everything in the rain, even tanks like Skarmory. Azumarill is also surprisingly bulky, and he is a good glue piece on my team. The only problems I have when I use Azumarill is Jellicent and Vaporeon. Ice Punch gives great coverage against many water absorbers (Dragonite, Celebi, etc.) and Super Power absolutely destroys Chansey and Blissey.

Starmie @Life Orb
Natural Cure
4 Def/252 SpA/252 Spe
Timid
-Hydro Pump
-Ice Beam
-Thunder
-Rapid Spin
Starmie does a surprising amount of damage coming from a base 100 SpA. Hydro Pump smashes through even things that resist it, and Bolt/Beam coverage is priceless. I do feel like this Starmie is too squishy and often dies very quickly, so I might switch out spin or Bolt/Beam for recover. I needed a spinner on my team since I use both genies very often. Starmie also pulls its own sweeps with its good speed and SpA.

Thundurus-T @Choice Scarf
Volt Absorb
4 Def/252 SpA/252 Spe
Timid
-Thunder
-Volt Switch
-HP Ice
-Focus Blast
I figured I would put in a strong abuser of Thunder since it's a rain team. Volt Switch is extremely useful, but it can be hard to use given all the ground types running around. Thundurus also goes down pretty quickly especially if there are rocks on the field or a sandstorm is raging. I often lead with an HP Ice just so Gliscor and the like don't get a free switch-in. It's nice to have a fast revenge killer, but Thundurus hasn't been absolutely amazing for me. I also put it in because I figured I needed more electric resists on the team. I'd definitely be willing to switch this thing out for a specially defensive Latias or something else.
Other options I've considered using for this team include:
choice scarf Terrakion
calm mind Keldeo
specially defensive Jirachi
specially defensive Latias
trickscarf Lati@s
Dragonite
Dugtrio
CB Scizor
Thanks a lot for any tips and checking out my rain team! Cheers