Yes I know, HG/SS hasnt been released yet and still I create a team based on it - But I've thought much about it and here it is:
Metagross @ Occaberry
Nature: +Atk - SAtk
EVs: 252,236,12,8,0,0
- Meteor Mash
- Earthquake
- Gravity
- Stealth Rocks
>>> It's the usual Lead Meta, but just with Gravity. It is with Jirachi the best Lead for a Gravity team I think because it is supposed to be as successfull as in a normal team.
Forretress@ Leftovers
Nature: +Def - Atk
EVs: 252,0,200,0,52,0
- Gravity
- Spikes
- Pain Split/Rapid Spin
- Zap Cannon
>>> Also one of the best gravity users for several reasons:
It can Spike which is really great since every Pokemon is weak to it in gravity and Zap Cannon has much more accurary and being like Thunderwave and Thunderbolt in one move! It also kills Gyarados, one of the main counters for Forry. I just cant decide between Rapid Spin and Pain Split :/ Spin because im also weak to spikes.
Mamoswine@ Life Orb
Nature: +Speed - SDef
EVs: 6,252,0,252,0,0
- Earthquake
- Blizzard
- Ice Shard
- Stone Edge
>>> Imo Mamoswine is almost obligatory in a gravity team having EQ as STAB, a great Atk and perfect (Bronzong is also hit in GV) coverage and the common counters (Skarm, Zong etc) have now chance since they are hit by EQ. Blzzard hits always like in hail and its better against Hippowdon for example, and btw Stone Edge also always hits.
Shaymin@ Leftovers
Nature: +Speed - Atk
EVs: 6,0,0,252,252,0
- Seed Flare
- Earth Power
- Grass Whistle
- Leech Seed/Rest
>>> Shaymn also is great in GV because of having a safe ground resistance (immunities are not that userful) and some moves taking advantage from GV: EP hits Skarm and other Flying Types, Seed Flare is 100% accure and Grass Whistle also an accurity of 92%. Its also bulky so that it can be easily switched in in Water Tanks etc.
Leech seed is for doing at least something against Bliss, take a TW or toxic and then heal it when switching out. Rest is just for healing and also takes advantage from Natural Cure.
Blissey@ Leftovers
Nature: +Def - Atk
EVs: 252,0,252,0,0,6
- Thunder/Blizzard/Fire Storm
- Soft-Boiled
- Gravity
- Seismic Toss/Aroma Therapy
>>> It almost always can use GV having switched into a special sweeper, and the three moves (which is best in this case?) have perfact accurary. It also walls every special sweeper of course.
Rotom-H@ Choice Scarf
Nature: +SAtk - Atk
EVs: 126,0,0,126,252,0
- Thunder
- Overheat
- Trick
- Will-o-wisp/Shadow Ball
>>> I know its hit by ground attacks in GV, but it fits perfectly to my team: its my ceck against Scizor, Gyarados, almost every Fighting Pkmn and a good revenger which helps with trick breaking stall.
WoW or Shadow Ball? WoW is useful for switch-ins and Machamp which can give me a payback, but Shadow Ball gives me more revenging qualities. And btw: WoW and Thunder alwas hit ;) And overheat, too lol
I hope you like my team :D
And Im German so ignore all grammar mistakes etc

Metagross @ Occaberry
Nature: +Atk - SAtk
EVs: 252,236,12,8,0,0
- Meteor Mash
- Earthquake
- Gravity
- Stealth Rocks
>>> It's the usual Lead Meta, but just with Gravity. It is with Jirachi the best Lead for a Gravity team I think because it is supposed to be as successfull as in a normal team.

Forretress@ Leftovers
Nature: +Def - Atk
EVs: 252,0,200,0,52,0
- Gravity
- Spikes
- Pain Split/Rapid Spin
- Zap Cannon
>>> Also one of the best gravity users for several reasons:
It can Spike which is really great since every Pokemon is weak to it in gravity and Zap Cannon has much more accurary and being like Thunderwave and Thunderbolt in one move! It also kills Gyarados, one of the main counters for Forry. I just cant decide between Rapid Spin and Pain Split :/ Spin because im also weak to spikes.

Mamoswine@ Life Orb
Nature: +Speed - SDef
EVs: 6,252,0,252,0,0
- Earthquake
- Blizzard
- Ice Shard
- Stone Edge
>>> Imo Mamoswine is almost obligatory in a gravity team having EQ as STAB, a great Atk and perfect (Bronzong is also hit in GV) coverage and the common counters (Skarm, Zong etc) have now chance since they are hit by EQ. Blzzard hits always like in hail and its better against Hippowdon for example, and btw Stone Edge also always hits.

Shaymin@ Leftovers
Nature: +Speed - Atk
EVs: 6,0,0,252,252,0
- Seed Flare
- Earth Power
- Grass Whistle
- Leech Seed/Rest
>>> Shaymn also is great in GV because of having a safe ground resistance (immunities are not that userful) and some moves taking advantage from GV: EP hits Skarm and other Flying Types, Seed Flare is 100% accure and Grass Whistle also an accurity of 92%. Its also bulky so that it can be easily switched in in Water Tanks etc.
Leech seed is for doing at least something against Bliss, take a TW or toxic and then heal it when switching out. Rest is just for healing and also takes advantage from Natural Cure.

Blissey@ Leftovers
Nature: +Def - Atk
EVs: 252,0,252,0,0,6
- Thunder/Blizzard/Fire Storm
- Soft-Boiled
- Gravity
- Seismic Toss/Aroma Therapy
>>> It almost always can use GV having switched into a special sweeper, and the three moves (which is best in this case?) have perfact accurary. It also walls every special sweeper of course.

Rotom-H@ Choice Scarf
Nature: +SAtk - Atk
EVs: 126,0,0,126,252,0
- Thunder
- Overheat
- Trick
- Will-o-wisp/Shadow Ball
>>> I know its hit by ground attacks in GV, but it fits perfectly to my team: its my ceck against Scizor, Gyarados, almost every Fighting Pkmn and a good revenger which helps with trick breaking stall.
WoW or Shadow Ball? WoW is useful for switch-ins and Machamp which can give me a payback, but Shadow Ball gives me more revenging qualities. And btw: WoW and Thunder alwas hit ;) And overheat, too lol
I hope you like my team :D
And Im German so ignore all grammar mistakes etc