Hey, it's the second time I (try to) make a competitive team and I may be need some help even know I found this team pretty cool ! Let's go :
Infernape @ Life Orb - Choice Band
Ability : Iron Fist
EVs : 252 Atk / 252 Spe / 4 HP - SpD
Nature : Jolly - Adamant
- Thunder Punch
- Fire Blitz - Fire Blast - Fire Punch
- Close Combat
- U-Turn - Mach Punch
This is the Pokemon I wanted in the core of this team but this is the Pokemon where I'm the most uncertain of everything. A set with the Life Orb is possible but it could a good idea to not play this with Fire Blitz since Infernape don't really got the longevity of a Blissey. Fire Blast may be an alternative but there will be a lack of power since this set don't really rely on SpA. so maybe our choices will be for Fire Punch that can easily OHKO Excadrill, Celebi or Mega-Scizor or 2HKO Defensive Skarmory. Close Combat is a powerfull STAB that annihilate (Mega-)Tyranitar, all set of Heatran and can do a serious amount of damage on the neutral. Thunder Punch is for coverage, and with Iron Fist, it can deal some pretty serious damage on some Pokemon OHKOing some set of Gyarados or Keldeo (even know Keldeo probably OHKO Infernape before since all of his set give the maximum EV to Speed and then out-run Infernape). U-Turn is here principally to play it safe with our monkey since I found him useful ! Mach Punch is an alternative but since Infernapes staying power is shitty, if it have to take priority on his side to hit his opponent, the opponent will probably hurt Infernape really badly.
Mega-Sharpedo Sharpedoite
Ability : Strong Jaws
EVs : 252 Atk / 252 Spe / 4 Def
Nature : Adamant - Jolly
- Crunch
- Waterfall
- Ice Fangs
- Earthquake
The second part of this core : M-Sharpedo ! I really like him but it's true that he's far from what we can call a Good OU Pokemon. Bad Def / SpD, 5 weakness, and a poor move pool. But he got some serious weapons with his Speed, his high Atk and his new ability : Strong Jaws. Crunch is the essential STAB with Waterfall since he OHKO M-Gallade, M-Gardevoir or M-Metagross. Waterfall is always a pretty STAB to OHKO Victini or Diggersby. Ice Fangs gives an opportunity to deals serious damage on Dragon like Flygon, Dragonite or M-Altaria and can OHKO Physically Defensive Gliscor, Offensive Landorus-T and 2HKO Physically Defensive Landorus-T. Earthquake is the alternative I choose against Protect + Speed Boost on Sharpedo before Mega-evolving to take down some possible threat like Non-Magnet Rise Magnezone, Heatran or just deal some good damage to Diancie or Mega-Charizard X. The Jolly Nature is a possibility here but you lose a lot of your power. I think it depends on your team.
Mamoswine @ Focus Sash - Leftovers
Ability : Oblivious
EVs : 252 Atk / 252 Spe / 4 Def
Nature : Jolly
- Stealth Rock
- Ice Shard
- Icicle Spear / Superpower / Stone Edge
- Earthquake
Mamoswine got the essential Stealth Rock + Oblivious so he can't be Taunt. Ice Shard + Mamoswines great Attack is for revenge killing already hurts Gliscor, Landorus and a lot of Dragons. Icicle Spear is one of Mamoswine STAB, the only problem is that it takes at least 3 hits to be really useful and OHKO weak Pokemons, 4 to OHKO Gliscor and probably 5 for Physically Defensive Landorus-T. Icicle Crash is an alternative for the ones who don't mind the 90% accuracy. Since you already got Ice Shard, Superpower or Stone Edge could possibly replace Icicle Spear/Crash. I personnaly choose Stone Edge against some global threats like Talonflame or M-Charizard Y but I think again that it depends on the rest of your team weakness. Earthquake is the main STAB here. With the Focus Sash, it can OHKO Dragon Dance M-Charizard X after a Fire Blitz. Leftovers could be a possibility to give Mamoswine more longevity.
Garchomp @ Rocky Helmet
Ability : Rough Skin
EVs : 252 HP / 164 Def / 76 SpD / 16 Spe
Nature : Impish
- Stealth Rock / Toxic
- Earthquake
- Fire Blast
- Dragon Tail
I always try to get to Pokemon with Stealth Rock because of Rapid Spinner / Defoger / Taunter... You don't really know if a lonely Pokemon will be able to play the entry hazard so I gave me a second chance to do so. This set is pretty simple Impish + this repartition give you a good tank and the Rocky Helmet/Rough Skin that hurt the audacious Pokemon that want to physically hit Garchomp. Dragon Tail to phazes your threats and bring a new friend that the Stealth Rock will prepare for Earthquake or Fire Blast. Earthquake have a good coverage and Fire Blast can go through the ones who are not afraid with Earthquake like M-Scizor (even if it doesn't OHKO it when he's full life) Toxic is really good alternative I just thought of since it could works really good with Gengar.
Gengar @ Black Sludge
Ability : Levitation
EVs : 248 SpA / 252 Spe / 8 HP
Nature : Timid
- Sludge Wave
- Will-O-Wisp
- Hex
- Taunt
Will-O-Wisp burn your opponents (if not already poisoned by Garchomp) and Hex + STAB + EVs + 130 Base SpA + Status = A colossal killing machine. Taunt is here against Heal Bellers, Aromathrapists, and other healers. Sludge Wave is the STAB to take down Normal Pokemons immune to Hex.
Sylveon @ Leftovers
Ability : Pixilate
EVs : 252 HP / 220 Def / 36 Spe - SpD
Nature : Bold
- Wish
- Heal Bell
- Protect
- Hyper Voice
It's a Cleric classic set. Wish to heal your Pokemon or Sylveon himself with the support of Protect. Heal Bell to cure the Status and finally Hyper Voice + Pixilate with Sylveons good 110 SpA base stat to hit pretty well your enemies. This repartition give the general bulk Sylveon needs against neutral attacks to heal.
And it's over! I often use something like Adamant - Jolly, it's because I dont really know which one could be the best. Like I said, this team seems pretty good to me but there's always a way to improve it, mostly because I'm just a begginer in strategy and I'm really curious to see how you can help me :)
P.S.: I'm french and do my best but it's possible that I made, like, a thousand mistakes so be kind to me haha

Infernape @ Life Orb - Choice Band
Ability : Iron Fist
EVs : 252 Atk / 252 Spe / 4 HP - SpD
Nature : Jolly - Adamant
- Thunder Punch
- Fire Blitz - Fire Blast - Fire Punch
- Close Combat
- U-Turn - Mach Punch
This is the Pokemon I wanted in the core of this team but this is the Pokemon where I'm the most uncertain of everything. A set with the Life Orb is possible but it could a good idea to not play this with Fire Blitz since Infernape don't really got the longevity of a Blissey. Fire Blast may be an alternative but there will be a lack of power since this set don't really rely on SpA. so maybe our choices will be for Fire Punch that can easily OHKO Excadrill, Celebi or Mega-Scizor or 2HKO Defensive Skarmory. Close Combat is a powerfull STAB that annihilate (Mega-)Tyranitar, all set of Heatran and can do a serious amount of damage on the neutral. Thunder Punch is for coverage, and with Iron Fist, it can deal some pretty serious damage on some Pokemon OHKOing some set of Gyarados or Keldeo (even know Keldeo probably OHKO Infernape before since all of his set give the maximum EV to Speed and then out-run Infernape). U-Turn is here principally to play it safe with our monkey since I found him useful ! Mach Punch is an alternative but since Infernapes staying power is shitty, if it have to take priority on his side to hit his opponent, the opponent will probably hurt Infernape really badly.

Mega-Sharpedo Sharpedoite
Ability : Strong Jaws
EVs : 252 Atk / 252 Spe / 4 Def
Nature : Adamant - Jolly
- Crunch
- Waterfall
- Ice Fangs
- Earthquake
The second part of this core : M-Sharpedo ! I really like him but it's true that he's far from what we can call a Good OU Pokemon. Bad Def / SpD, 5 weakness, and a poor move pool. But he got some serious weapons with his Speed, his high Atk and his new ability : Strong Jaws. Crunch is the essential STAB with Waterfall since he OHKO M-Gallade, M-Gardevoir or M-Metagross. Waterfall is always a pretty STAB to OHKO Victini or Diggersby. Ice Fangs gives an opportunity to deals serious damage on Dragon like Flygon, Dragonite or M-Altaria and can OHKO Physically Defensive Gliscor, Offensive Landorus-T and 2HKO Physically Defensive Landorus-T. Earthquake is the alternative I choose against Protect + Speed Boost on Sharpedo before Mega-evolving to take down some possible threat like Non-Magnet Rise Magnezone, Heatran or just deal some good damage to Diancie or Mega-Charizard X. The Jolly Nature is a possibility here but you lose a lot of your power. I think it depends on your team.

Mamoswine @ Focus Sash - Leftovers
Ability : Oblivious
EVs : 252 Atk / 252 Spe / 4 Def
Nature : Jolly
- Stealth Rock
- Ice Shard
- Icicle Spear / Superpower / Stone Edge
- Earthquake
Mamoswine got the essential Stealth Rock + Oblivious so he can't be Taunt. Ice Shard + Mamoswines great Attack is for revenge killing already hurts Gliscor, Landorus and a lot of Dragons. Icicle Spear is one of Mamoswine STAB, the only problem is that it takes at least 3 hits to be really useful and OHKO weak Pokemons, 4 to OHKO Gliscor and probably 5 for Physically Defensive Landorus-T. Icicle Crash is an alternative for the ones who don't mind the 90% accuracy. Since you already got Ice Shard, Superpower or Stone Edge could possibly replace Icicle Spear/Crash. I personnaly choose Stone Edge against some global threats like Talonflame or M-Charizard Y but I think again that it depends on the rest of your team weakness. Earthquake is the main STAB here. With the Focus Sash, it can OHKO Dragon Dance M-Charizard X after a Fire Blitz. Leftovers could be a possibility to give Mamoswine more longevity.

Garchomp @ Rocky Helmet
Ability : Rough Skin
EVs : 252 HP / 164 Def / 76 SpD / 16 Spe
Nature : Impish
- Stealth Rock / Toxic
- Earthquake
- Fire Blast
- Dragon Tail
I always try to get to Pokemon with Stealth Rock because of Rapid Spinner / Defoger / Taunter... You don't really know if a lonely Pokemon will be able to play the entry hazard so I gave me a second chance to do so. This set is pretty simple Impish + this repartition give you a good tank and the Rocky Helmet/Rough Skin that hurt the audacious Pokemon that want to physically hit Garchomp. Dragon Tail to phazes your threats and bring a new friend that the Stealth Rock will prepare for Earthquake or Fire Blast. Earthquake have a good coverage and Fire Blast can go through the ones who are not afraid with Earthquake like M-Scizor (even if it doesn't OHKO it when he's full life) Toxic is really good alternative I just thought of since it could works really good with Gengar.

Gengar @ Black Sludge
Ability : Levitation
EVs : 248 SpA / 252 Spe / 8 HP
Nature : Timid
- Sludge Wave
- Will-O-Wisp
- Hex
- Taunt
Will-O-Wisp burn your opponents (if not already poisoned by Garchomp) and Hex + STAB + EVs + 130 Base SpA + Status = A colossal killing machine. Taunt is here against Heal Bellers, Aromathrapists, and other healers. Sludge Wave is the STAB to take down Normal Pokemons immune to Hex.

Sylveon @ Leftovers
Ability : Pixilate
EVs : 252 HP / 220 Def / 36 Spe - SpD
Nature : Bold
- Wish
- Heal Bell
- Protect
- Hyper Voice
It's a Cleric classic set. Wish to heal your Pokemon or Sylveon himself with the support of Protect. Heal Bell to cure the Status and finally Hyper Voice + Pixilate with Sylveons good 110 SpA base stat to hit pretty well your enemies. This repartition give the general bulk Sylveon needs against neutral attacks to heal.
And it's over! I often use something like Adamant - Jolly, it's because I dont really know which one could be the best. Like I said, this team seems pretty good to me but there's always a way to improve it, mostly because I'm just a begginer in strategy and I'm really curious to see how you can help me :)
P.S.: I'm french and do my best but it's possible that I made, like, a thousand mistakes so be kind to me haha