Gen 8 NU
Druddigon @ Yache Berry
Ability: Mold Breaker
EVs: 252 HP / 16 Atk / 124 SpD / 116 Spe
Adamant Nature
- Earthquake
- Gunk Shot
- Stealth Rock
- Glare
This set had some usage in NUPL (Never Used Premier League). Mold Breaker and Stealth Rock allow you to set up Stealth Rock without having to worry about Xatu's Magic Bounce. Glare is to spread paralysis on opposing Pokemon. Earthquake and Gunk Shot provides good coverage and hits all Pokemon in the tier (bar Aerodactyl) for neutral or super effective damage.
EV Spread Analysis:
You're probably thinking that the EV spread is weird, so I'll do my best to break it down. 252 HP EVs is pretty obvious. 124 Special Defense EVs allow you to take a Sludge Wave from Salazzle better if Stealth Rock is on your side.
252 SpA Salazzle Sludge Wave vs. 252 HP / 124 SpD Druddigon: 133-157 (37.1 - 43.8%) -- 0.4% chance to 2HKO after Stealth Rock
Possible damage amounts: (133, 135, 136, 138, 139, 141, 142, 144, 145, 147, 148, 150, 151, 153, 154, 157)
You can even survive a +2 Sludge Wave from Salazzle, but don't switch directly into Salazzle's Sludge Wave so you can survive a +2 Sludge Wave from Salazzle and hit back.
+2 252 SpA Salazzle Sludge Wave vs. 252 HP / 124 SpD Druddigon: 265-313 (74 - 87.4%) -- guaranteed 2HKO after Stealth Rock
Possible damage amounts: (265, 268, 271, 274, 279, 282, 285, 288, 291, 294, 297, 300, 303, 306, 309, 313)
116 Speed EVs puts Druddigon at 161 speed, allowing you to outspeed Sylveon and max speed Adamant Copperajah. The rest of the EVs are in attack because they are leftover EVs that give your attacks a little more power. Yache Berry allows you to tank a hit from a +2 Ice Beam from Shell Smash Blastoise really well.
252+ SpA Blastoise Ice Beam vs. 252 HP / 124 SpD Yache Berry Druddigon: 78-92 (21.7 - 25.6%) -- 100% chance to 4HKO after Stealth Rock
Possible damage amounts: (78, 79, 80, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92)