It's my first time on here so let's see how this goes!
A lot of these pokemon were chosen with no specific synergy in mind, I mainly just chose them initially because I think they're cool lol. I haven't tested or anything, but in my opinion this has the potential to be a pretty powerful team. I think each pokemon has something unique that it brings to the table and their resistances and coverage work well overall.
Hydreigon @ Life Orb
Nature: Mild/Rash
Ability: Levitate
EVs: 4 HP/252 SpA/252 Spe
- Draco Meteor
- Fire Blast
- Superpower
- Earthquake
Hydreigon is all about power and coverage. I've used him before and he's a force to be reckoned with. Draco Meteor smashes through just about anything in its path with hydreigon's amazing SpA and life orb. It makes him useful as a powerful wall-breaker too. Everything else was chosen for having the best coverage possible.
Conkeldurr @ Flame Orb
Nature: Adamant
Ability: Guts
EVs: 128 HP/252 Atk/128 SpD
- Drain Punch
- Mach Punch
- Ice Punch
- Payback
Just like hydreigon, I've used conkeldurr before and with excellent results. My friend almost refused to battle me for a while simply because of conkeldurr. I used to use him with bulk up and no status orb equipped, but I think this will be much more effective. In my experience conkeldurr is bulky enough as is, and I've even had him take hits from STAB psychic moves and be able to take out the opponent the next turn with a good old mach punch. Seeing as his biggest weakness is generally in the form of psychic moves, bulk up wouldn't do him much good defensively, so I opted to take an extra attack and use the flame orb so he gets his immense attack to even higher levels right off the bat.
Jolteon @ Choice Specs
Nature: Timid
Ability: Volt Absorb
EVs: 252 SpA/4 SpD/252 Spe
- Volt Switch
- Thunderbolt
- Shadow Ball
- HP Grass/Ice
I chose Jolteon because he's always been one of my favourite pokemon, and even though I've never used him, I think he could be a powerful special attacker. I've got volt switch so that I can send him out and hopefully force a switch, allowing me to scout the opponent's team and switch in with a counter. Thunderbolt is obviously there for a good old STAB, and the rest are for coverage. Choosing between HP grass and ice I wasn't quite sure, seeing as grass can be used to hit the nasty water/ground types that would have no fear of electric attacks, but ice provides safety against dragon types.
Gliscor @ Toxic Orb
Nature: Impish
Ability: Poison Heal
EVs: 252 HP/184 Def/72 Spe
- Toxic
- Protect
- Taunt
- Earthquake
Gliscor plays the role as my physical wall. Earthquake is the obvious attack choice. Toxic helps wear down the opponent's pokemon and alongside protect it makes gliscor a good stallbreaker too. I like taunt because again it messes with the opponent's walls which is always good, and I don't think any of my other pokemon can learn it.
Ferrothorn @ Rocky Helmet
Nature: Relaxed
Ability: Iron Barbs
EVs: 252 HP/88 Def/168 SpD
- Spikes
- Stealth Rock
- Gyro Ball
- Power Whip
Ferrothorn works as both a mixed wall and a trap setter. I have the rocky helmet on there because it works well with iron barbs, and I couldn't think of anything else to use. I've considered using explosion instead of gyro ball seeing as he has no recovery, so that I can set spikes and stealth rock, then when he gets worn down I can just make him go boom :) I wasn't sure about that however because I like ferrothorn as an option aside from jolteon to take out water types, hence power whip. I think thunder wave might be ok as well in place of gyro ball.
Vaporeon @ Leftovers
Nature: Bold
Ability: Water Absorb
EVs: 248 HP/252 Def/8 Spe
- Wish
- Protect
- Roar
- Scald
I chose vaporeon because his type weaknesses fit well with the rest of my team and I like what he brings to the table with wish. Wish allows vaporeon to heal either himself, or another pokemon that I switch in, essentially giving me a free switch and depending on what the opponent does, potentially fully healing a pokemon. Protect is there to make vaporeon more durable and it works well with wish. I would mainly use vaporeon as a special wall, so I was thinking of taking some EVs off Def and onto SpD, but lemme know what you think. Roar works nicely with spikes and stealth rock to lay on some damage. Scald is a decent attack and is nice with the potential burn.
I was considering using jellicent with recover, will-o-wisp, scald and ice beam rather than vaporeon because I believe he is a more durable special wall, but seeing as he wouldn't be as useful beyond that I decided not to.
Let me know what you think though, and if I should make any changes!