So here is a Team Weakness checker that I like to use when building my team, Link
Now I put in your current team and here is what I got,
What stand out is
- 2x weakness to Fighting
- 3x weakness to Ground
Otherwise it's not too bad.
Rotom-W
The set you currently run on Rotom is good, but you have the wrong EVs to take advantage of it. Rotom pairs quite well with Forretress so what we can do is ake Rotom specially defensive.
Rotom-W @ Leftovers
Trait: Levitate
EVs: 252 HP / 200 SDef / 56 SAtk
Calm Nature
- Will-O-Wisp
- Pain Split
- Hydro Pump
- Volt Switch
Classic SDef Rotom-W with a few more EVs invested in SAtk to allow you to hit a little harder. Again it pairs extremely well with Forretress and gives you a nice strong Defensive core.
Scizor
Scizor is a very strong attacker and I like your use but unfortunately with Forretress he doesn't make the best of team mates on this team. You also lack special attackers so we can make that switch. I'll be incorporating Gengar here as it is a nice speedy annoying guy who is a dear to use. He also draws in Dark moves for a switch to Terra for a Justified boost.
There are a couple sets you can try the first of which is a SubDisable set which I find to be highly annoying.
Gengar @ Black Sludge
Trait: Levitate
EVs: 252 SAtk / 252 Spd / 4 HP
Timid Nature
- Substitute
- Disable
- Shadow Ball
- Focus Blast
I absolutely hate taking down this type of Gengar, it is extremely annoying to use. If you prefer a more offensive set then I would go for LO Gengar which deals punches that no one likes to take.
Gengar @ Life Orb
Trait: Levitate
EVs: 252 SAtk / 252 Spd / 4 HP
Timid Nature
- Shadow Ball
- Focus Blast
- Thunderbolt
- Pain Split/Giga Drain
When holding LO you want to make sure that your total HP cannot be divided by 10 to reduce the recoil. Now you will be getting recoil so you can go for one of two recovery moves, Giga Drain and Pain Split. They both have their merits, Giga Drain does damage and can hit Ground, Rock, and Water types hard. Pain Split can work on anyone but works especially well on walls who generally have more HP. Focus Blast and Shadow Ball are your two main moves and provide good coverage beside each other. That's all for this little guy, let's move on.
Breloom
Breloom is a troll but he doesn't quite work in this team as he gives you an additonal psychic weakness with Gengar here. So we'll be replacing him with a dark type. After some consideration I added Hydreigon as he did more good then bad with your team synergy. You also need a Scarfer and Hydreigon does very well as a scarfer, So I'll provide that set.
Hydreigon @ Choice Scarf
Trait: Levitate
EVs: 252 SAtk / 252 Spd / 4 HP
Timid Nature
- Draco Meteor
- Fire Blast
- Surf
- Dark Pulse
This is my favorite set to use although it can't hit Gastro with anything although it won't like taking a DMeteor on the switch in. Fire Blast is preferred for power > accuracy although you can go Flamethrower if you prefer having better accuracy. Dark Pulse is secondary STAB while Surf is coverage for unsaid Heatrans. Timid nature is too add some needed speed as Hydreigon has a lower speed then his counter parts the Lati twins.
You can also try running this set which is what my friend AlphaDraconis uses.
Hydreigon @ Choice Scarf
Trait: Levitate
EVs: 60 HP / 252 SpA / 196 Spe
Timid Nature
- Draco Meteor
- Earth Power
- Fire Blast/Flamethrower
- Hidden Power [Dark]
HP Dark because Earth Power and Dark Pulse are incompatible on Showdown. The rest is somewhat the same as above. Spread is somewhat different allowing for a little more bulk.
Houndoom
Now with Hydreigon in the mix we have a fighting weakness, I said we would be adding a dark type but what I hadn't told you was that I would be replacing Houndoom. He added a ground and Fighting weakness to the original team and there were other who could fill his place which is why he got replaced. So I'm going to put in someone who doesn't resist fighting types but hits them quite hard, Metagross. His weakness to Fire and Ground are covered by the rest of your team so you should be fine using him. I'm going to suggest one of my favorite Meta sets, Agility.
Metagross @ Lum Berry
Trait: Clear Body
EVs: 252 Atk / 204 Spd / 52 HP
Jolly Nature
- Meteor Mash
- Earthquake/Ice Punch
- Zen Headbutt
- Agility
The one poke you have problems with on this set is Skarm. So if the opponent has Skarm, take it down before using Meta. There isn't anything to hit dragons (unless you go Ice Punch > EQ) but Meteor Mash will destroy them so no worries there. EQ can hit Ferro for neutral damage and it will eventually kill it unless it Seed Stalls you. The 204 EVs allow you to outspeed Lando by 2 points :3. Thanks to Alpha for helping me on the EVs.
Forretress
Classic Forre. I like it, works well for the team. All I changed was the nature to give you more power for Gyro Ball.
Forretress @ Leftovers
Trait: Sturdy
EVs: 252 Def / 252 HP / 4 Atk
Relaxed Nature
IVs: 0 Spd
- Rapid Spin
- Spikes
- Stealth Rock
- Gyro Ball
Terrakion
Terrakion is good, I really like using Terra. Originally I was thinking he could be your Scarfer but after Hydreigon I decided he could run a Choice Band set. It is my favorite set to run and hits incredibly hard.
Terrakion @ Choice Band
Trait: Justified
EVs: 252 Atk / 252 Spd / 4 HP
Jolly Nature
- Stone Edge
- Earthquake
- Close Combat
- X-Scissor
EdgeQuake combo with STAB CC and X-Sci to hit grass and psychic type like Celebi and Reuniclus. Not much else to say about him, he's a true beast.
This is your new team with the synergy, it doesnt include abilities so it's going to say Ground: 4 Weak but you only have two weak and you have three resists. Fighting still has more weaknesses then full out resists, but you have a couple pokes, like Forretress, who can take a fighting attack with ease. Other then that everything else is good with more resists then weaknesses.