This is a Fire, Water, Grass Team. It functions a little like other core teams. But most other core teams die out when one member of the core faints. I tried my best to create a team so that they don't die easily but if they do then the team wont completely crumble. I did my best to tell you how in all of the core pokemons explanation. I've patched all the things that I can think of, but of course this is smogon and if you guys see a dent you can hopefully help me buff it out.
I've ran this team on Pokemon Online when it was in its beginning stages but, back then I had a Vaporeon instead of Quagsire and an Arcanine instead of Volcarona. They were replaced to hopefully make the team better, but I still think it needs to be looked over a lot.
Lead:
Kabutops @ Focus Sash
Battle Armor
Adamant
Atk +252 / Sp +252 / Hp +4
-Stealth Rock
-Rapid Spin
-Stone Edge
-Aqua Jet
His first priority is to take out the opposing lead if it can get super effective damage. Infernape, Heatran, Donphan, Hippowdon are all common leads that take super effective damage. If he does not get super effective damage it can just set up SR like normal leads do.
He can come in for the Rapid Spin every once in a while to make sure Volcarona doesn't get absolutely screwed.
The only problems I've been running into are Gengar and Ferrothorn Leads. Gengar can take me out easily with focus blast. Ferrothorn, I just can't do anything to it, and it can hit me with Power Whip for x4 damage.
Core:
Quagsire @ Leftovers
Unaware
Bold
Hp +252 / Def +252 / SpD +4
-Recover
-Stockpile
-Swagger
-Scald
Chosen over other water types because of its synergy with the team. Its the peanut butter to my Blissey's jelly and its unaware ability can put a stop to most boosting sweepers, such as; RP Terrakion, SD Scizor, and DD Gyarados / Dragonite. Not only that but it pulls in Grass types for either Shaymin to set up on. It also draws in Grass types for either Heracross or Volcarona to sweep on.
Scald is his Stab water move to hopefully get a burn off of. Stockpile better sets up his somewhat low defenses. Recover is an instant source of health. And Swagger compliments scald so that he can get a confusion along with a burn, and because of his ability he doesn't have to worry about their attack boost. (Lots of thanks to No Luck Involved for giving me the idea for this set)
Core:
Volcarona @ Leftovers
Flame Body
Modest
SpA +252 / Sp +252 / SpD +4
-Fire Blast
-Bug Buzz
-Morning Sun
-Quiver Dance
Comes in on all Grass, Bug, and Ice types that Shaymin did the courtesy of attracting. He has remarkable Special Attack and Speed that can be boosted tremendously by Quiver Dance. After a few turns to set up he can become an extremely effective sweeper, and can take Special hits like crazy. With Morning Sun to heal up with, Volcarona is something to fear.
If Volcarona faints then the team can still function. Mainly Heracross taking his place. It will be difficult but Heracross can come in on all the grass type moves Volcarona would've normally come in on. Also, Quagsire can take care of all the Ice types that Volcarona normally would've came in on.
Core:
Shaymin @ Leftovers
Natural Cure
Calm
Hp +252 / SpD +128 / Def 128
-Leech Seed
-Rest
-Earth Power
-Seed Flare
Shaymin helps the core by setting up Leech Seed for everyone to heal off of. And special walls like Blissey and Snorlax that try to absorb the Seed Flare end up becoming massive Hp sources to my team. Rest is to Heal himself up just incase he can't make use of the Leech Seed much. He not only rounds up Fire types for Quagsire, but he can also round up Ice types and bug types (like Scizor or Frosslass) for Volcarona.
He also sets up very nicely for Heracross to come in. Heracross doesn't have a way to heal himself and Shaymins Leech Seed Helps him there. And any Poison type that threatens Shaymin can be taken down with his Earthquake.
Revenge Killer:
Heracross @ Choice Scarf
Moxie
Jolly
Atk +252 / Sp +252 / Hp +4
-Close Combat
-Megahorn
-Stone Edge
-Earthquake
Do you remember how I mentioned Gengar and Ferrothorn Leads threaten my Kabutops. Well Heracross can outspeed both and can get get super effective damage on them. Which is absolutely awesome. Moxie boost for a hopeful chance at a late game sweep.
A great moveset, typing, a chance to sweep, and great speed, all make it the perfect choice for a revenge killer.
Honestly, this thing can holds up the core more than anything. If anyone of the core members faint then Heracross can normally take its place and try to do its best. Which is why I will most likely will not use any other Revenge Killer.
Cleric:
Blissey @ Leftovers
Natural Cure
Bold
Hp +252 / Def +252 / SpD +4
-Heal Bell
-Softboil
-Toxic
-Seismic Toss
Blissey is the cleric on the team. She was chosen so she can heal Shaymin and Suicune from their rest. She is also a great Toxic staller, with access to a way to heal herself, softboil. She has Seismic Toss in her moveset so that she can at least deal a little bit of damage without having to invest into her attack stats.