I've been battling competitively for about a year now and being a more defensive player than most I decided to make a little more offensive oriented team based of resistances and bulk rather than just walls. So here it goes :D
Jirachi @Leftovers
Nature: Impish
EVs: 240 Hp 160 Def 76 SpD 32 Spe
Moveset:
Body Slam
Iron Head
Stealth Rock
Wish
I needed a lead to this team that would be unexpected and original, and Jirachi, having its amazing movepool fit the bill. When people see Jirachi they are always like ' Oh another TrickScarf Rachi ' and they switch in their Heatran or Flygon only to be in shock when I body Slam and Paralyze their Choice Scarf pokemon. Next depending on what they switch in I Stealth Rock or Switch into an appropiate counter. Wish is there for team support and that extra bulk and Iron Head for Aerodactyl, Tyranitar, Azelf, Wish + Flinch combo, and for STAB. The only problem I found with this Jirachi is Infernape and Heatran, the former usually switches because it doesnt want to get flinched. Also Bronzong and Metagross resist the whole moveset and I usually just set up Stealth Rocks and try to paralyze the Metagross in case its Trick Scarf.
Celebi @ Leftovers
Nature: Bold
Evs: 252 Hp 220 Def 32 Spe
Moveset:
Leech Seed
Grassknot
Recover
Thunderwave
Well I know what you are thinking, Celebi with no HP Fire? Scizor bait. This might technically be true but on this team I have so many Scizor counters I found HP Fire pretty repetitive and useless. Leech seed allows me to take advantage of those Blissey and Snorlax switches and also take hits better from Pokemon like Zapdos. Thunderwave is essential because of the amazing team support that it proves and the fully paralysis that might help me pull off a sweep. Grassknot for STAB and incoming Tyranitars and Recover to get back my health. Celebi is a great defensive wall and is incredibly bulky on both spectrums. It has great synergy with Heatran, Jirachi, and Gyarados.
Gyarados @ Leftovers
Nature: Adamant
EVs: 156 Hp 108 Atk 100 Def 144 Spe
Moveset:
Waterfall
Taunt
Stone Edge
Dragon Dance
Standard Bulky Gyarados. One of my favorite sets. Taunt lets me come in on those walls and stop them from recovering or using status on my Gyarados. Bulky Gyarados takes some hits and allows me to get that very much needed 2nd dragon dance ensuring a sweep. I usually don't bring him out til i get rid of Vaporeon, and Heatran provides perfect bait for that. He also is a great counter to Mixape and has great synergy with Jirachi, and usually can be healed with a Wish improving its duribility. Waterfall is for STAB and Stone Edge is for the great coverage it provides.
Rotom-H @ Choice Scarf
Nature: Modest
EVs: 252 SpA 252 Spe 6 Hp
Moveset:
Trick
Thunderbolt
Overheat
Shadowball
This little toaster here is AMAZING. Rotom-H works perfect with my, revenge killing those pesky Gengars that can do a number to my team. Also doing a lot of damage to Latias and OHKOing after some residual damage. Also with its signature move Overheat it allows me to counter Crunch Lucario any day of the week, as well as Scizor and Forretress. Trick is there for Blissey, Snorlax, Swampert, or CM Suicune that try and ruin the fun. While Thunderbolt hits Heatran who think they can switch in for free, and Shadowball for a powerful stab. Tyranitar loves switching into this guy though and I usually end up losing that fight unless it DD's while I switch out. But then I can just switch into Machamp and threaten, while also being able to set up.
Machamp @ Leftovers
Nature: Adamant
EVs: 252 Hp 252 Atk 6 Spe
Moveset:
Dynamicpunch
Payback
Stone Edge
Substitute
Machamp is the perfect fit to this team because of how much Tyranitar wants to switch into my Pokemon. With its resistances to Bug, Rock, and Dark it provides the ultimate synergy to my team. Machamp is a reliable and bulky Pokemon that can dent anything it hits. Substitute allows me to set up on Blissey and Tyranitar and makes Machamp even more bulky and a lot harder to handle. Sub also allows me to scout for those Ghost switches and then gives me the chance to payback and eliminate them allowing me to use Dynamic Punch freely. Fighting Rock and Dark gets perfect coverage and it is why i used this set. The only thing that can sort of wall me is Gliscor but I have plenty on this team to handle that.
Heatran @ Leftovers
Nature: Timid
EVs: 252 Speed 252 SpA 6 Hp
Moveset:
Toxic
Substitute
Fire Blast
Earthpower
Subtran ! Subtran is perfect on this team because of all the paralysis support it gets. I keep subbing down til i have a free sub and usually get a couple free hits in. Toxic is for Swampert, and Vaporeon. This slowly wears them down and helps my Gyarados sweep a lot better. I usually come in on Fire moves directed at Jirachi and Celebi, play it off that I have a scarf and then set up a sub and go from there. Fire Blast for Flashfire + STAB and Earth Power for the ever so common heatran switch and hitting steels Fire Blast wouldnt. Subtrans work amazingly these days. I also might try out a Sub Salac tran, gives me a Free boost without choice scarf and with its typing I can take the main Priority moves out there like Ice Shard, Bullet Punch and Extremespeed. But for now Ill work with this as it has great Synergy with Celebi and helps my Gyarados pull of its sweeps.
Well thats my team. I hope it was detailed enough and provided enough information. I havent really found any real threats that I couldnt handle on this team. Starmie sort of can do some damage, but I always have Scarf Rotom for the revenge and Machamp to take some hits and Payback. Well thats pretty much it. I hope you guys like my team :]

Jirachi @Leftovers
Nature: Impish
EVs: 240 Hp 160 Def 76 SpD 32 Spe
Moveset:
Body Slam
Iron Head
Stealth Rock
Wish
I needed a lead to this team that would be unexpected and original, and Jirachi, having its amazing movepool fit the bill. When people see Jirachi they are always like ' Oh another TrickScarf Rachi ' and they switch in their Heatran or Flygon only to be in shock when I body Slam and Paralyze their Choice Scarf pokemon. Next depending on what they switch in I Stealth Rock or Switch into an appropiate counter. Wish is there for team support and that extra bulk and Iron Head for Aerodactyl, Tyranitar, Azelf, Wish + Flinch combo, and for STAB. The only problem I found with this Jirachi is Infernape and Heatran, the former usually switches because it doesnt want to get flinched. Also Bronzong and Metagross resist the whole moveset and I usually just set up Stealth Rocks and try to paralyze the Metagross in case its Trick Scarf.

Celebi @ Leftovers
Nature: Bold
Evs: 252 Hp 220 Def 32 Spe
Moveset:
Leech Seed
Grassknot
Recover
Thunderwave
Well I know what you are thinking, Celebi with no HP Fire? Scizor bait. This might technically be true but on this team I have so many Scizor counters I found HP Fire pretty repetitive and useless. Leech seed allows me to take advantage of those Blissey and Snorlax switches and also take hits better from Pokemon like Zapdos. Thunderwave is essential because of the amazing team support that it proves and the fully paralysis that might help me pull off a sweep. Grassknot for STAB and incoming Tyranitars and Recover to get back my health. Celebi is a great defensive wall and is incredibly bulky on both spectrums. It has great synergy with Heatran, Jirachi, and Gyarados.

Gyarados @ Leftovers
Nature: Adamant
EVs: 156 Hp 108 Atk 100 Def 144 Spe
Moveset:
Waterfall
Taunt
Stone Edge
Dragon Dance
Standard Bulky Gyarados. One of my favorite sets. Taunt lets me come in on those walls and stop them from recovering or using status on my Gyarados. Bulky Gyarados takes some hits and allows me to get that very much needed 2nd dragon dance ensuring a sweep. I usually don't bring him out til i get rid of Vaporeon, and Heatran provides perfect bait for that. He also is a great counter to Mixape and has great synergy with Jirachi, and usually can be healed with a Wish improving its duribility. Waterfall is for STAB and Stone Edge is for the great coverage it provides.

Rotom-H @ Choice Scarf
Nature: Modest
EVs: 252 SpA 252 Spe 6 Hp
Moveset:
Trick
Thunderbolt
Overheat
Shadowball
This little toaster here is AMAZING. Rotom-H works perfect with my, revenge killing those pesky Gengars that can do a number to my team. Also doing a lot of damage to Latias and OHKOing after some residual damage. Also with its signature move Overheat it allows me to counter Crunch Lucario any day of the week, as well as Scizor and Forretress. Trick is there for Blissey, Snorlax, Swampert, or CM Suicune that try and ruin the fun. While Thunderbolt hits Heatran who think they can switch in for free, and Shadowball for a powerful stab. Tyranitar loves switching into this guy though and I usually end up losing that fight unless it DD's while I switch out. But then I can just switch into Machamp and threaten, while also being able to set up.

Machamp @ Leftovers
Nature: Adamant
EVs: 252 Hp 252 Atk 6 Spe
Moveset:
Dynamicpunch
Payback
Stone Edge
Substitute
Machamp is the perfect fit to this team because of how much Tyranitar wants to switch into my Pokemon. With its resistances to Bug, Rock, and Dark it provides the ultimate synergy to my team. Machamp is a reliable and bulky Pokemon that can dent anything it hits. Substitute allows me to set up on Blissey and Tyranitar and makes Machamp even more bulky and a lot harder to handle. Sub also allows me to scout for those Ghost switches and then gives me the chance to payback and eliminate them allowing me to use Dynamic Punch freely. Fighting Rock and Dark gets perfect coverage and it is why i used this set. The only thing that can sort of wall me is Gliscor but I have plenty on this team to handle that.

Heatran @ Leftovers
Nature: Timid
EVs: 252 Speed 252 SpA 6 Hp
Moveset:
Toxic
Substitute
Fire Blast
Earthpower
Subtran ! Subtran is perfect on this team because of all the paralysis support it gets. I keep subbing down til i have a free sub and usually get a couple free hits in. Toxic is for Swampert, and Vaporeon. This slowly wears them down and helps my Gyarados sweep a lot better. I usually come in on Fire moves directed at Jirachi and Celebi, play it off that I have a scarf and then set up a sub and go from there. Fire Blast for Flashfire + STAB and Earth Power for the ever so common heatran switch and hitting steels Fire Blast wouldnt. Subtrans work amazingly these days. I also might try out a Sub Salac tran, gives me a Free boost without choice scarf and with its typing I can take the main Priority moves out there like Ice Shard, Bullet Punch and Extremespeed. But for now Ill work with this as it has great Synergy with Celebi and helps my Gyarados pull of its sweeps.
Well thats my team. I hope it was detailed enough and provided enough information. I havent really found any real threats that I couldnt handle on this team. Starmie sort of can do some damage, but I always have Scarf Rotom for the revenge and Machamp to take some hits and Payback. Well thats pretty much it. I hope you guys like my team :]