This metagame is filled with offensive teams. This is not one of them.
When I was building this team, the goal was to safely counter every Pokemon that I could come across in the OU tier, and punish the opponent on switches with entry hazards, and I think this team does a pretty good job of this.
Team Building:
When I was thinking of the core of this team, I wanted a FWG core, that could have utility beyond just taking hits. In the end, I decided on a core of Heatran, Celebi, and Jellicent (female because it's cooler :P).
From there I needed someone to set hazards up safely, namely spikes. After testing with Skarmory, Cloyster, and even Drapion for toxic spikes, I settled on Forretress, because he is the most dependable Pokemon for getting up Spikes or Toxic Spikes (or both). Now the team looks like this.
At this point, Celebi was the one setting up Stealth Rocks, and it really needed that extra move slot, so I went with another synergy pair of Gliscor (for Stealth Rocks) and Rotom-Wash, for the final two Pokemon, making the final team look like this.
The team:
Celebi @ Leftovers
Trait: Natural Cure
EVs: 252 HP/252 Def/4 SpD
Bold Nature
-Heal Bell
-Psychic
-Recover
-Perish Song
To put it simply, Celebi is the glue to this team. I decided on physically defensive Celebi due to the ground and fighting weaknesses of Heatran and the lack of physical bulk of Jellicent. The way this Celebi functions is as a set up stopper with Perish Song, and as a cleric. All of my Pokemon are walls, and three of them carry Rest because Celebi can get them right back into the game with a single Heal Bell. Perish Song pseudo-phazes, adding on the the entry hazard damage, and Psychic destroys Toxicroak, and this Celebi especially counters Breloom if sleep-clause is activiated, which it often is due to so many Pokemon with Rest. Synergy wise Celebi works great with Jellicent and Heatran. Most importantly, it can take the Earthquakes that neither of those two want to take. It is one of three physical walls on the team.
Heatran @ Leftovers
Trait: Flash Fire
EVs: 252 HP/252 SpD/4 SpA
-Roar
-Protect
-Lava Plume
-Rest
Heatran is my main counter to Sun teams, and a member of the FWG core. The way this Heatran functions is it phazes, Protect stalls, and prevents Ferrothorn and Forretress from setting up all over me. As the only phazer on the team, it is extremely important that I keep this guy alive. Without reliable recovery? Rest and heal bell do wonders for Heatran, and can even scare some people out thinking it's a rest-talk set. In terms of synergy, Heatran works great for Celebi, taking fire attacks, and protecting to see if they are choiced or not. It's major weakness to ground is covered by Celebi, and it's fighting weakness is covered by Celebi and Jellicent and even Gliscor. It is one of three special walls on the team.
Jellicent @ Leftovers
Trait: Water Absorb
EVs: 252 HP/222 SpD/36 Def
Calm Nature
-Will O Wisp
-Recover
-Scald
-Ice Beam
Jellicent is the final member of the FWG core. It functions as a spin blocker as well as a great special sponge. This Jellicent counters Starmie and scares Forretress. Will-o-wisp just wears down the opponent, along with the entry hazards and constant switches this team forces. Recover is again for reliable recovery, because this team just does not die. Scald hit's incoming physical threats and can possibly burn, whereas Ice Beam is solely for Latias and Latios, which would otherwise beat this team. In terms of synergy it's weakness to grass is covered by Forretress, Heatran, and Celebi. It's weakness to electric is covered by Gliscor, Celebi, and even Rotom-W. Jellicent basically sponges everything.
Gliscor @ Toxic Orb
Trait: Poison Heal
EVs: 252 HP/184 Def/72 Spe
Bold Nature
-Stealth Rock
-Roost
-Toxic
-Taunt
Gliscor usually functions as my lead. It can come in and taunt slower Pokemon, and proceed to safely set up Stealth Rocks. The reasoning behind Bold nature is that it doesn't even carry a single attacking move, so I may as well lower the Attack as much as possible in case of Confusion. Late game, Gliscor walls most all fighting types, and can toxic them or force a switch if it's an obvious choice Pokemon. Gliscor does wonders for this team. It gives me a second resistance to fighting, along with the immunity from Jellicent, so I can play a lot of mind games with choiced Infernapes and fighting types in general. Also, it is one of only two ground immunities, and it's weaknesses are covered by the FWG core. Roost is just for staying power. Gliscor is one of three Physical Walls.
Rotom-W @ Leftovers
Trait: Levitate
EVs: 252 HP/252 SpD/4 Def
Calm Nature
-Thunder Wave
-Thunderbolt
-Hydro Pump
-Rest
Rotom-W does a lot for my team, he is a secondary water type special wall to Jellicent, which gives me a lot of insurance there, and it is my standard lead against rain teams. The way this Rotom-W functions is as a special wall, that comes in and paralysis threats such as Latias and Latios, making them an easy kill for Jellicent. Rotom-W has a lot of synergy with Gliscor, making a great pair of Pokemon for the team. In addition, Rotom-W gives me another much needed fire resistance, as well as one of only two ground immunities. It's weaknesses are covered by the FWG core. Rest is another recovery move on this team. Rotom-W is one of three special walls on this team.
Forretress @ Leftovers
Trait: Sturdy
EVs: 252 HP/252 Def/4 SpD
Impish Nature
-Spikes
-Toxic Spikes
-Rapid Spin
-Rest
Forretress sets up hazards, and spins them away. That's all it does. It's my main counter to Outrage, as well as physically based Pokemon in general. Forretress can always get up at least one layer of Spikes or Toxic Spikes due to Sturdy, though with a proper switch in I can usually get at least three layers up. Most players try to get an obvious spinner out of the game early, and Forretress does not have reliable recovery such as Roost, therefore, I put Rest on it. Giving Forretress an extra life or two to keep the threat of a spinner, or to put up more hazards puts a lot of pressure on the opponent. In terms of synergy, there really isn't much, but that doesn't matter, all it does it put up hazards, and spins them away. It is also one of three physical walls on the team.
Recap:
This team is a huge stall team, and relies on entry hazards to win.
Thank you for reading, and I am open to any suggestions except adding weather.
Thank you.
When I was building this team, the goal was to safely counter every Pokemon that I could come across in the OU tier, and punish the opponent on switches with entry hazards, and I think this team does a pretty good job of this.
Team Building:
When I was thinking of the core of this team, I wanted a FWG core, that could have utility beyond just taking hits. In the end, I decided on a core of Heatran, Celebi, and Jellicent (female because it's cooler :P).



From there I needed someone to set hazards up safely, namely spikes. After testing with Skarmory, Cloyster, and even Drapion for toxic spikes, I settled on Forretress, because he is the most dependable Pokemon for getting up Spikes or Toxic Spikes (or both). Now the team looks like this.




At this point, Celebi was the one setting up Stealth Rocks, and it really needed that extra move slot, so I went with another synergy pair of Gliscor (for Stealth Rocks) and Rotom-Wash, for the final two Pokemon, making the final team look like this.






The team:

Celebi @ Leftovers
Trait: Natural Cure
EVs: 252 HP/252 Def/4 SpD
Bold Nature
-Heal Bell
-Psychic
-Recover
-Perish Song
To put it simply, Celebi is the glue to this team. I decided on physically defensive Celebi due to the ground and fighting weaknesses of Heatran and the lack of physical bulk of Jellicent. The way this Celebi functions is as a set up stopper with Perish Song, and as a cleric. All of my Pokemon are walls, and three of them carry Rest because Celebi can get them right back into the game with a single Heal Bell. Perish Song pseudo-phazes, adding on the the entry hazard damage, and Psychic destroys Toxicroak, and this Celebi especially counters Breloom if sleep-clause is activiated, which it often is due to so many Pokemon with Rest. Synergy wise Celebi works great with Jellicent and Heatran. Most importantly, it can take the Earthquakes that neither of those two want to take. It is one of three physical walls on the team.

Heatran @ Leftovers
Trait: Flash Fire
EVs: 252 HP/252 SpD/4 SpA
-Roar
-Protect
-Lava Plume
-Rest
Heatran is my main counter to Sun teams, and a member of the FWG core. The way this Heatran functions is it phazes, Protect stalls, and prevents Ferrothorn and Forretress from setting up all over me. As the only phazer on the team, it is extremely important that I keep this guy alive. Without reliable recovery? Rest and heal bell do wonders for Heatran, and can even scare some people out thinking it's a rest-talk set. In terms of synergy, Heatran works great for Celebi, taking fire attacks, and protecting to see if they are choiced or not. It's major weakness to ground is covered by Celebi, and it's fighting weakness is covered by Celebi and Jellicent and even Gliscor. It is one of three special walls on the team.

Jellicent @ Leftovers
Trait: Water Absorb
EVs: 252 HP/222 SpD/36 Def
Calm Nature
-Will O Wisp
-Recover
-Scald
-Ice Beam
Jellicent is the final member of the FWG core. It functions as a spin blocker as well as a great special sponge. This Jellicent counters Starmie and scares Forretress. Will-o-wisp just wears down the opponent, along with the entry hazards and constant switches this team forces. Recover is again for reliable recovery, because this team just does not die. Scald hit's incoming physical threats and can possibly burn, whereas Ice Beam is solely for Latias and Latios, which would otherwise beat this team. In terms of synergy it's weakness to grass is covered by Forretress, Heatran, and Celebi. It's weakness to electric is covered by Gliscor, Celebi, and even Rotom-W. Jellicent basically sponges everything.

Gliscor @ Toxic Orb
Trait: Poison Heal
EVs: 252 HP/184 Def/72 Spe
Bold Nature
-Stealth Rock
-Roost
-Toxic
-Taunt
Gliscor usually functions as my lead. It can come in and taunt slower Pokemon, and proceed to safely set up Stealth Rocks. The reasoning behind Bold nature is that it doesn't even carry a single attacking move, so I may as well lower the Attack as much as possible in case of Confusion. Late game, Gliscor walls most all fighting types, and can toxic them or force a switch if it's an obvious choice Pokemon. Gliscor does wonders for this team. It gives me a second resistance to fighting, along with the immunity from Jellicent, so I can play a lot of mind games with choiced Infernapes and fighting types in general. Also, it is one of only two ground immunities, and it's weaknesses are covered by the FWG core. Roost is just for staying power. Gliscor is one of three Physical Walls.

Rotom-W @ Leftovers
Trait: Levitate
EVs: 252 HP/252 SpD/4 Def
Calm Nature
-Thunder Wave
-Thunderbolt
-Hydro Pump
-Rest
Rotom-W does a lot for my team, he is a secondary water type special wall to Jellicent, which gives me a lot of insurance there, and it is my standard lead against rain teams. The way this Rotom-W functions is as a special wall, that comes in and paralysis threats such as Latias and Latios, making them an easy kill for Jellicent. Rotom-W has a lot of synergy with Gliscor, making a great pair of Pokemon for the team. In addition, Rotom-W gives me another much needed fire resistance, as well as one of only two ground immunities. It's weaknesses are covered by the FWG core. Rest is another recovery move on this team. Rotom-W is one of three special walls on this team.

Forretress @ Leftovers
Trait: Sturdy
EVs: 252 HP/252 Def/4 SpD
Impish Nature
-Spikes
-Toxic Spikes
-Rapid Spin
-Rest
Forretress sets up hazards, and spins them away. That's all it does. It's my main counter to Outrage, as well as physically based Pokemon in general. Forretress can always get up at least one layer of Spikes or Toxic Spikes due to Sturdy, though with a proper switch in I can usually get at least three layers up. Most players try to get an obvious spinner out of the game early, and Forretress does not have reliable recovery such as Roost, therefore, I put Rest on it. Giving Forretress an extra life or two to keep the threat of a spinner, or to put up more hazards puts a lot of pressure on the opponent. In terms of synergy, there really isn't much, but that doesn't matter, all it does it put up hazards, and spins them away. It is also one of three physical walls on the team.
Recap:
This team is a huge stall team, and relies on entry hazards to win.
Thank you for reading, and I am open to any suggestions except adding weather.
Thank you.