I was wondering if I could get some advice on my team this my first team to build so take it easy lol and it's for doubles.
Hydreigon
Life orb
Draco meteor
Flamethrower
Dark pulse
Protect
MetagRoss
Mega stone
Meteor mash
Ice punch
Zen headbutt
Protect
Rotom
Leftovers
Will o wisp
Thunderbolt
Hydro pump
Protect
Chandelure
Focus sash
Shadow ball
Energy ball
Heat wave
Protect
Hitmonlee
Knock off
High jump kick
Stone edge
Protect
Mamoswine
Icicle shard
Earthquake
Superpower
Protect
Last 2 don't have items yet I'm not sure for them. Any help would be much appreciated.
This is an impressive line-up for your first team build, so you've got a good start! You should probably plan out the nature and EV's you're using for each Pokemon though. For example, that Hydreigon could definitely benefit from a spread of 4 HP/252 Special Attack/252 Speed with a Timid nature. If you need any advice on that, I'd be happy to help.
As for move and item structure, Hydreigon could have its Life Orb replaced with a Choice Scarf and Protect replaced with Earth Power. Hydreigon is known for being one of the best users of the Choice Scarf in the Double Battles scene, but you should prepare to make predictions about your opponent's moves and make sure you have something to switch out into at all times.
That Metagross set is actually the exact set I've been running in Doubles currently and I'm glad to see it in your arsenal! No further comments on that
That Rotom set is also the standard Rotom set that I've been using. It does wonders in the current format and is an all around solid Pokemon. My only qualm is that if you're building this team in game, the EV spread for a standard Rotom is VERY awkward, but is hand-crafted by competitive players to stack up against the likes of Mega Salamence and Mega Mawile. The spread is Calm nature with 252 HP/116 Defense/4 Special Attack/132 Special Defense/4 Speed.
Chandelure is a bit of a mixed bag in my book. It's one of my favorite Pokemon from both a design and competitive standpoint, but I've never been fully confident using it in Doubles. The set seems fine to me, though I would probably suggest throwing Substitute on it over Energy Ball. I wouldn't concern myself with keeping a lot of coverage moves on Chandy, just make sure that the partner you send him out with complements him. You could also use Life Orb just for damage output, but I understand why the Sash is appealing.
Hitmonlee is the one thing here that threw me off. It's a cool Pokemon, but in my experience has been too frail for Double battling, just because most attacks can kill it or bring it into range to be taken out by moves like Heat Wave and Rock Slide. If I could make a suggestion, perhaps replace the Lee with a Hitmontop, who is known for being an excellent Double battling Pokemon simply because of the ability Intimidate. I also recommend switching the moveset around a bit, since Hitmontop is much more of a support Pokemon than its more offensive Single-battling cousin. My recommended set is Fake Out (an amazing Double battles move), Close Combat, Knock Off, and Wide Guard (used for blocking those moves such as Heat Wave and Hyper Voice). For an item, Sitrus Berry seems to be a good contender!
Lastly is a Pokemon that I actually just started playing around with. Mamoswine is a very strong option in Doubles due to its amazing control over the board with multi-hitting and priority moves (ergo Ice Shard and Earthquake which you already have listed, so points for picking some damn good moves!) My suggestion though would be to replace Superpower with Icicle Crash. As I said with Chandelure, as long as you pair it up well, you won't need to use more coverage options on Mamo. Just being able to have more damage options is a very good idea. For item, I'm always a proponent of Focus Sash Mamoswine, but if it's on Chandelure, we'll have to come up with something better. Life Orb is a good pick just to maximize your damage if Chandelure is Sashed, but if you choose to put the Orb on Chandelure, Focus Sash is always an incredible item for Mamoswine.
Sorry for this post being so wordy, it's the only way I can properly articulate my thoughts. Either way, hope this comprehensive guide to your team helps you out, and good luck battling!