Here are a few sets I quite like, that I've done well with
Set Up Sweeper
Serperior @ Leftovers / Grassium Z
Ability: Contrary
Timid Nature
EVs: 252 SpA / 4 SpD / 252 Spe
- Leaf Storm
- Dragon Pulse / Hidden Power [Ice]
- Hidden Power [Rock] / Hidden Power [Fire] / Giga Drain
- Giga Drain / Synthesis
Pure offence EV's, enough said.
Bulky Support Contrary
Serperior @ Aguav Berry / Leftovers
Ability: Contrary
Timid Nature
EVs: 200 HP / 36 SpA / 252 Spe
- Leaf Storm
- Hidden Power [Fire] / Hidden Power [Rock]
- Glare
- Substitute
EV's are for semi bulk, to take hits better, while racking up Special Attack boosts. Glare to cripple, and Sub to dodge status. With the above EVs, you can activate the Berry after the third sub, with Stealth Rock damage, or one layer of Spikes, or after the 4th Sub, with less than 1% HP left, with no prior damage. If you wanted a guaranteed Berry Activation on the 3rd Sub, you can play around with the EV's.
Physical Attacker
Serprior @ Leftovers / Aguav Berry / Steelium Z / Waterium Z / Grassium Z
Ability: Overgrow
Jolly Nature
EVs: 248 HP / 84 Atk / 4 SpD / 172 Spe
- Leaf Blade
- Iron Tail / Aqua Tail
- Coil
- Synthesis
Speed EVs allow it to outspeed anything unboosted up to base 102, with Neutral Nature, and base 90 with a beneficial nature. 4 Special Defense because of Download Ability, against this Serp, they'll always get Physical Attack. Porygon and it's evolved forms arent super common, but 4 EVs in HP or Def/Sp Def is common, and when a Pokemon has equal base defences, I do 4 Sp Def, just in case. Decent bulk to live medium strength Super Effective hits, and strong neutral ones. Item choice is pretty versatile, and depends largely on what else is on your team. I generally run Battle Bond Greninja, and some sort of Dragon, so I'd opt for Iron Tail over Aqua Tail.