As I've recently started building teams to use, I would like to present you the team I had the most success with in ladder and tournament games.
https://pokepast.es/f9f8487dc2729ee6 - This is the paste if you don't want to read the rest of the post.This idea originally came to me when I heard my friends talking about how good cm clef can be, so I thought as I don't use cm clef or clef very often i will give it a shot at building.

Skarmory @ Rocky Helmet
Ability: Sturdy
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Spikes,
- Roost,
- Whirlwind,
- Counter,

Clefable @ Life Orb
Ability: Magic Guard
EVs: 248 HP / 216 Def / 44 Spe
Bold Nature
IVs: 0 Atk
- Moonblast,
- Thunder,
- Soft-Boiled,
- Calm Mind,
I started the idea with these 2, as i wanted hazard support to help clefable break down other teams checks to clef such as heatran, kartana and heart swap magearna,spikes also act nicely to help reduce the longevity of threats to this team, such as taunt lele, mega ttar, 3 attacks ZardX after mega. 44 speed on clefable is to outspeed heart swap magearnasand also outspeed pokemon at 331 speed or less that get paralysed by thunder on the off chance it does. Skarmory fits quite nicely here to help deal with SD excadrill on sand, Mgyara with counter/whirlwind, SD bulu, Msciz and such.

Gliscor @ Toxic Orb
Ability: Poison Heal
EVs: 244 HP / 244 SpD / 20 Spe
Careful Nature
- Stealth Rock,
- Earthquake,
- Knock Off,
- Roost,
Gliscor is the next addition to the team, i didnt have a stealth rocker and I was weak to heatran, so it felt like a no-brainer. I prefer Careful and really bulky gliscors to eat hits from hpice landos, uninvested icebeam from magearna and other neutral attacks from strong special attackers such as mega alakazam. I also noticed the team lacked knock off which is crucial vs other fat structures and acts as a status absorber quite nicely. Gliscor helps clefable break through.

Cresselia @ Leftovers
Ability: Levitate
EVs: 252 HP / 92 Def / 152 SpA / 12 Spe
Bold Nature
- Psyshock,
- Ice Beam,
- Calm Mind,
- Moonlight,
Next up is cresselia, at the moment I LOVE this mon, the fact it can sit on most things and just outright win the game is nuts. Cresselia plays a key role in checking lopunny,medicham whilst also making the psyspam matchup better by giving a bulky psychic resist.

Latias-Mega) (F) @ Latiasite
Ability: Levitate
EVs: 248 HP / 8 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Roost,
- Psychic,
- Draco Meteor,
- Surf,
Latias is on the team to not just get rolled over by manaphy, stall rain turns against swampert under rain and dish out draco meteors to threaten kyurem black and SD ZardX. This Latias has surf to threaten ttars on switch in and chip them down to not lose to them later in the game.

Toxapex @ Black Sludge
Ability: Regenerator
EVs: 252 HP / 92 Def / 164 SpD
Calm Nature
IVs: 0 Atk
- Toxic Spikes,
- Scald,
- Toxic/Haze,
- Recover,
Lastly, Toxapex, pressure bulky teams and defogless offenses such like XTRA and certain psyspams etc. Pex also serves as a swap-in to greninja to scout the set.This team without haze toxapex struggles against volcarona but you can opt for toxic pex to put defoggers on a timer and pressure opposing cm cress'.
THREAT LIST:
CM Cress depending on pex set
Volcarona depending on pex set
Encore/Taunt Alakazam
DDance CharX
Manaphy
DD Mega ttar
Shoutout to my son
Abele for helping with sets