This team's been doing fairly well, nothing outstanding. I think most of my losses come from misplaying rather than the team itself, but I'm sure there's still plenty of things to fix. I based the team around setting up for a Gyarados sweep. I don't want the team to be solely reliant on Gyarados for its offensive needs but as it is right now when Gyarados goes down earlier than I'd like I almost completely lack offensive power as Heatran and Scizor are easily walled when they're choiced.
Heatran (M) @ Choice Scarf
Ability: Flash Fire
EVs: 4 HP/252 Spd/252 SAtk
Mild nature (+SAtk, -Def)
- Earth Power
- Fire Blast
- Explosion
- Hidden Power [Ice]
Typical Scarftran. I went with Mild over Hasty because I didn't think I needed to outspeed anything where I would need a +speed nature. I didn't find a dedicated lead really necessary for my team. Also explodes on bulky waters and Porygon2 which Gyarados otherwise can't get past. I wanted to use BaitTran but ScarfTran was generally more useful and it can still explode.
Scizor (M) @ Choice Band
Ability: Technician
EVs: 156 HP/252 Atk/100 Spd
Adamant nature (+Atk, -SAtk)
- Bullet Punch
- Superpower
- Pursuit
- U-turn
CB Scizor is just generally really useful for revenge-killing and stuff. Pursuit is also nice for weakening Psychic-types like Celebi, Cresselia, Starmie, and Slowbro to open up for a Gyarados sweep.
Gyarados (M) @ Leftovers
Ability: Intimidate
EVs: 52 HP/252 Atk/204 Spd
Adamant nature (+Atk, -SAtk)
- Dragon Dance
- Waterfall
- Stone Edge
- Earthquake
I went for enough speed to outspeed base 120s after a DD... I haven't found a need for more speed yet except for the occasional Jolteon, and I don't think it's worth losing all that power by switching to Jolly just for one Pokemon (although I've been seeing quite a lot of Jolteon...)
Swampert (M) @ Leftovers
Ability: Torrent
EVs: 240 HP/216 Def/52 SAtk
Relaxed nature (+Def, -Spd)
- Stealth Rock
- Roar
- Earthquake
- Ice Beam
I went for both SR and Roar because I didn't think the water move was completely necessary. Swampert sets up SR really easily. Roar is useful to scout the team early on so that I can see Gyarados counters. Lack of reliable recovery really hurts (except from Jirachi's Wish, but it's not always easy to pass Wish...), but Swampert's still a solid switch-in to Heatran and other prominent threats.
Jirachi @ Leftovers
Ability: Serene Grace
EVs: 240 HP/56 Atk/76 Def/136 Spd
Impish nature (+Def, -SAtk)
- Iron Head
- Wish
- U-turn
- Thunder Wave
Jirachi provides nice support in Wish (mainly for Gyarados, although pretty much the whole team benefits from Wish) and paralysis, and is also my initial switch-in to a lot of threats; although it can't take down a lot, paralysis helps my generally slow team take down things it otherwise wouldn't be able to. I'm thinking of taking out Iron Head for Zen Headbutt so that Jirachi can deal with water- and fighting-types better.
Celebi @ Leftovers
Ability: Natural Cure
EVs: 252 HP/220 Def/36 Spd
Bold nature (+Def, -Atk)
- Grass Knot
- Recover
- Reflect
- Hidden Power [Fire]
Celebi is mainly here to solve my problems with fighters and opposing Gyarados. Reflect prevents Celebi from getting seriously crippled by Pursuit. HP Fire is there so that Celebi can actually fight back against Lucario and other non-Heatran steels. I think I want to make this Celebi a bit more offensive and specially defensive because right now its been largely setup-fodder, and hasn't been the solid counter to bulky waters, Zapdos, and Jolteon that this team kind of needs.
Thanks in advance for your help! :)

Heatran (M) @ Choice Scarf
Ability: Flash Fire
EVs: 4 HP/252 Spd/252 SAtk
Mild nature (+SAtk, -Def)
- Earth Power
- Fire Blast
- Explosion
- Hidden Power [Ice]
Typical Scarftran. I went with Mild over Hasty because I didn't think I needed to outspeed anything where I would need a +speed nature. I didn't find a dedicated lead really necessary for my team. Also explodes on bulky waters and Porygon2 which Gyarados otherwise can't get past. I wanted to use BaitTran but ScarfTran was generally more useful and it can still explode.

Scizor (M) @ Choice Band
Ability: Technician
EVs: 156 HP/252 Atk/100 Spd
Adamant nature (+Atk, -SAtk)
- Bullet Punch
- Superpower
- Pursuit
- U-turn
CB Scizor is just generally really useful for revenge-killing and stuff. Pursuit is also nice for weakening Psychic-types like Celebi, Cresselia, Starmie, and Slowbro to open up for a Gyarados sweep.

Gyarados (M) @ Leftovers
Ability: Intimidate
EVs: 52 HP/252 Atk/204 Spd
Adamant nature (+Atk, -SAtk)
- Dragon Dance
- Waterfall
- Stone Edge
- Earthquake
I went for enough speed to outspeed base 120s after a DD... I haven't found a need for more speed yet except for the occasional Jolteon, and I don't think it's worth losing all that power by switching to Jolly just for one Pokemon (although I've been seeing quite a lot of Jolteon...)

Swampert (M) @ Leftovers
Ability: Torrent
EVs: 240 HP/216 Def/52 SAtk
Relaxed nature (+Def, -Spd)
- Stealth Rock
- Roar
- Earthquake
- Ice Beam
I went for both SR and Roar because I didn't think the water move was completely necessary. Swampert sets up SR really easily. Roar is useful to scout the team early on so that I can see Gyarados counters. Lack of reliable recovery really hurts (except from Jirachi's Wish, but it's not always easy to pass Wish...), but Swampert's still a solid switch-in to Heatran and other prominent threats.

Jirachi @ Leftovers
Ability: Serene Grace
EVs: 240 HP/56 Atk/76 Def/136 Spd
Impish nature (+Def, -SAtk)
- Iron Head
- Wish
- U-turn
- Thunder Wave
Jirachi provides nice support in Wish (mainly for Gyarados, although pretty much the whole team benefits from Wish) and paralysis, and is also my initial switch-in to a lot of threats; although it can't take down a lot, paralysis helps my generally slow team take down things it otherwise wouldn't be able to. I'm thinking of taking out Iron Head for Zen Headbutt so that Jirachi can deal with water- and fighting-types better.

Celebi @ Leftovers
Ability: Natural Cure
EVs: 252 HP/220 Def/36 Spd
Bold nature (+Def, -Atk)
- Grass Knot
- Recover
- Reflect
- Hidden Power [Fire]
Celebi is mainly here to solve my problems with fighters and opposing Gyarados. Reflect prevents Celebi from getting seriously crippled by Pursuit. HP Fire is there so that Celebi can actually fight back against Lucario and other non-Heatran steels. I think I want to make this Celebi a bit more offensive and specially defensive because right now its been largely setup-fodder, and hasn't been the solid counter to bulky waters, Zapdos, and Jolteon that this team kind of needs.
Thanks in advance for your help! :)