Insanely Optimized Clef:
Clefable @ Life Orb
Ability: Magic Guard
EVs: 136 HP / 144 Def / 40 SpA / 140 SpD / 48 Spe
Modest Nature
IVs: 0 Atk
- Moonblast
- Flamethrower/Ice Beam/Thunderbolt/Focus Blast/Grass Knot/Psychic/Shadow Ball
- Flamethrower/Ice Beam/Thunderbolt/Focus Blast/Grass Knot/Psychic/Shadow Ball
- Soft-Boiled
This is an offensively-oriented Clef that uses her deep Special movepool and optimized natural durability to threaten, and ultimately 1v1, many metagame threats.
48 Speed IVs outspeed Neutral Melmetal, which you 2HKO if it's offensive.
The vast majority of the above mons can be 2HKO'd by Moonblast or a coverage move. I lean toward Flamethrower and Ice Beam, just based on what's popular in the tier right now, but it's highly customizable to whatever you wanna smack the shit outta - namely Thunderbolt for Pex and Slowbro, or Focus Miss if you wanna get spicy for Heatran. It functions like Nidoking in the sense that good predictions make this Clef incredibly difficult to switch into confidently.
Works on a wide variety of teams, particularly Dragonspam, as you're taking out opposing Dragon types and chipping everything else. Stealth Rock support is nice to secure KOs, since you don't set it yourself. You could, but you're losing valuable coverage.
Use this thing, it's good.

Clefable @ Life Orb
Ability: Magic Guard
EVs: 136 HP / 144 Def / 40 SpA / 140 SpD / 48 Spe
Modest Nature
IVs: 0 Atk
- Moonblast
- Flamethrower/Ice Beam/Thunderbolt/Focus Blast/Grass Knot/Psychic/Shadow Ball
- Flamethrower/Ice Beam/Thunderbolt/Focus Blast/Grass Knot/Psychic/Shadow Ball
- Soft-Boiled
This is an offensively-oriented Clef that uses her deep Special movepool and optimized natural durability to threaten, and ultimately 1v1, many metagame threats.
48 Speed IVs outspeed Neutral Melmetal, which you 2HKO if it's offensive.
252+ Atk Choice Band Barraskewda Flip Turn vs. 136 HP / 144 Def Clefable in Rain: 253-298 (69.3 - 81.6%) -- guaranteed 2HKO
252+ Atk Bisharp Iron Head vs. 136 HP / 144 Def Clefable: 306-360 (83.8 - 98.6%) -- guaranteed 2HKO
252+ SpA Choice Specs Blacephalon Flamethrower vs. 136 HP / 140 SpD Clefable: 255-301 (69.8 - 82.4%) -- guaranteed 2HKO
252 SpA Choice Specs Dragapult Shadow Ball vs. 136 HP / 140 SpD Clefable: 153-181 (41.9 - 49.5%) -- guaranteed 3HKO
+1 252+ Atk Dragapult Phantom Force vs. 136 HP / 144 Def Clefable: 247-292 (67.6 - 80%) -- guaranteed 2HKO
+2 252 Atk Dragonite Dual Wingbeat (2 hits) vs. 136 HP / 144 Def Clefable: 290-344 (79.4 - 94.2%) -- approx. 2HKO
252 Atk Life Orb Garchomp Earthquake vs. 136 HP / 144 Def Clefable: 231-273 (63.2 - 74.7%) -- guaranteed 2HKO
0 SpA Heatran Magma Storm vs. 136 HP / 140 SpD Clefable: 127-151 (34.7 - 41.3%) -- guaranteed 3HKO
252 Atk Choice Band Kartana Leaf Blade vs. 136 HP / 144 Def Clefable: 306-361 (83.8 - 98.9%) -- guaranteed 2HKO
252+ SpA Choice Specs Transistor Regieleki Thunderbolt vs. 136 HP / 140 SpD Clefable: 285-336 (78 - 92%) -- guaranteed 2HKO
252+ Atk Choice Band Rillaboom Grassy Glide vs. 136 HP / 144 Def Clefable in Grassy Terrain: 258-304 (70.6 - 83.2%) -- guaranteed 2HKO
252+ SpA Choice Specs Tapu Lele Psyshock vs. 136 HP / 144 Def Clefable in Psychic Terrain: 303-357 (83 - 97.8%) -- guaranteed 2HKO
252+ SpA Choice Specs Tapu Lele Psychic vs. 136 HP / 140 SpD Clefable in Psychic Terrain: 297-349 (81.3 - 95.6%) -- guaranteed 2HKO
252+ Atk Choice Band Tyranitar Stone Edge vs. 136 HP / 144 Def Clefable: 297-351 (81.3 - 96.1%) -- guaranteed 2HKO
252 Atk Choice Band Urshifu-Rapid-Strike Surging Strikes (3 hits) vs. 136 HP / 144 Def Clefable on a crit: 300-354 (82.1 - 96.9%) -- approx. 2HKO
252 SpA Choice Specs Volcanion Sludge Wave vs. 136 HP / 140 SpD Clefable: 294-346 (80.5 - 94.7%) -- guaranteed 2HKO
+2 252 SpA Volcarona Flamethrower vs. 136 HP / 140 SpD Clefable: 285-336 (78 - 92%) -- guaranteed 2HKO
252 Atk Choice Band Weavile Triple Axel (40 BP) (3 hits) vs. 136 HP / 144 Def Clefable: 306-360 (83.8 - 98.6%) -- approx. 2HKO
252 Atk Choice Band Zapdos-Galar Brave Bird vs. 136 HP / 144 Def Clefable: 309-364 (84.6 - 99.7%) -- guaranteed 2HKO
+2 252+ Atk Hawlucha Acrobatics (110 BP) vs. 136 HP / 144 Def Clefable: 337-397 (92.3 - 108.7%) -- 50% chance to OHKO (shh)
252 Atk Excadrill Iron Head vs. 136 HP / 144 Def Clefable: 290-344 (79.4 - 94.2%) -- guaranteed 2HKO
252+ Atk Life Orb Technician Scizor Bullet Punch vs. 136 HP / 144 Def Clefable: 307-361 (84.1 - 98.9%) -- guaranteed 2HKO
252+ Atk Bisharp Iron Head vs. 136 HP / 144 Def Clefable: 306-360 (83.8 - 98.6%) -- guaranteed 2HKO
252+ SpA Choice Specs Blacephalon Flamethrower vs. 136 HP / 140 SpD Clefable: 255-301 (69.8 - 82.4%) -- guaranteed 2HKO
252 SpA Choice Specs Dragapult Shadow Ball vs. 136 HP / 140 SpD Clefable: 153-181 (41.9 - 49.5%) -- guaranteed 3HKO
+1 252+ Atk Dragapult Phantom Force vs. 136 HP / 144 Def Clefable: 247-292 (67.6 - 80%) -- guaranteed 2HKO
+2 252 Atk Dragonite Dual Wingbeat (2 hits) vs. 136 HP / 144 Def Clefable: 290-344 (79.4 - 94.2%) -- approx. 2HKO
252 Atk Life Orb Garchomp Earthquake vs. 136 HP / 144 Def Clefable: 231-273 (63.2 - 74.7%) -- guaranteed 2HKO
0 SpA Heatran Magma Storm vs. 136 HP / 140 SpD Clefable: 127-151 (34.7 - 41.3%) -- guaranteed 3HKO
252 Atk Choice Band Kartana Leaf Blade vs. 136 HP / 144 Def Clefable: 306-361 (83.8 - 98.9%) -- guaranteed 2HKO
252+ SpA Choice Specs Transistor Regieleki Thunderbolt vs. 136 HP / 140 SpD Clefable: 285-336 (78 - 92%) -- guaranteed 2HKO
252+ Atk Choice Band Rillaboom Grassy Glide vs. 136 HP / 144 Def Clefable in Grassy Terrain: 258-304 (70.6 - 83.2%) -- guaranteed 2HKO
252+ SpA Choice Specs Tapu Lele Psyshock vs. 136 HP / 144 Def Clefable in Psychic Terrain: 303-357 (83 - 97.8%) -- guaranteed 2HKO
252+ SpA Choice Specs Tapu Lele Psychic vs. 136 HP / 140 SpD Clefable in Psychic Terrain: 297-349 (81.3 - 95.6%) -- guaranteed 2HKO
252+ Atk Choice Band Tyranitar Stone Edge vs. 136 HP / 144 Def Clefable: 297-351 (81.3 - 96.1%) -- guaranteed 2HKO
252 Atk Choice Band Urshifu-Rapid-Strike Surging Strikes (3 hits) vs. 136 HP / 144 Def Clefable on a crit: 300-354 (82.1 - 96.9%) -- approx. 2HKO
252 SpA Choice Specs Volcanion Sludge Wave vs. 136 HP / 140 SpD Clefable: 294-346 (80.5 - 94.7%) -- guaranteed 2HKO
+2 252 SpA Volcarona Flamethrower vs. 136 HP / 140 SpD Clefable: 285-336 (78 - 92%) -- guaranteed 2HKO
252 Atk Choice Band Weavile Triple Axel (40 BP) (3 hits) vs. 136 HP / 144 Def Clefable: 306-360 (83.8 - 98.6%) -- approx. 2HKO
252 Atk Choice Band Zapdos-Galar Brave Bird vs. 136 HP / 144 Def Clefable: 309-364 (84.6 - 99.7%) -- guaranteed 2HKO
+2 252+ Atk Hawlucha Acrobatics (110 BP) vs. 136 HP / 144 Def Clefable: 337-397 (92.3 - 108.7%) -- 50% chance to OHKO (shh)
252 Atk Excadrill Iron Head vs. 136 HP / 144 Def Clefable: 290-344 (79.4 - 94.2%) -- guaranteed 2HKO
252+ Atk Life Orb Technician Scizor Bullet Punch vs. 136 HP / 144 Def Clefable: 307-361 (84.1 - 98.9%) -- guaranteed 2HKO
The vast majority of the above mons can be 2HKO'd by Moonblast or a coverage move. I lean toward Flamethrower and Ice Beam, just based on what's popular in the tier right now, but it's highly customizable to whatever you wanna smack the shit outta - namely Thunderbolt for Pex and Slowbro, or Focus Miss if you wanna get spicy for Heatran. It functions like Nidoking in the sense that good predictions make this Clef incredibly difficult to switch into confidently.
Works on a wide variety of teams, particularly Dragonspam, as you're taking out opposing Dragon types and chipping everything else. Stealth Rock support is nice to secure KOs, since you don't set it yourself. You could, but you're losing valuable coverage.
Use this thing, it's good.