Shedinja @ Focus Sash

Trait: Wonder Guard
EVs: 252 Attck / 252 Speed / 4 Special Defense
Lonely Nature (+Atk, -Def)
Swords Dance
X-Scissor
Shadow Sneak
Will-O-Wisp
Serperior @ Big Root

Trait: Overgrow
EVs: 186 HP / 68 Attack / 96 Defense / 160 Speed
Careful Nature (+SpA, -SpD)
Leaf Blade
Hidden Power [Water]
Giga Drain
Toxic
Bastiodon @ Leftovers

Trait: Sturdy
EVs: 252 HP / 252 Special Defense / 4 Defense
Imsish Nature (+Def, -SpA)
Stealth Rock
Earthquake
Toxic
Stone Edge
Walrein @ Leftovers

Trait: Thick Fat
EVs: 252 HP / 6 Defense / 252 Special Defense
Calm Nature (+SpD, -Atk)
Protect
Ice Beam
Toxic
Hidden Power [Fire]
Muk @ Black Sludge

Trait: Poison Touch
EVs: 56 HP / 92 Defense / 110 Special Attack / 252 Special Defense
Brave Nature (+Atk, -Spe)
Poison Jab
Sleep Talk
Rest
Hidden Power [Ice]
Articuno @ Leftovers

Trait: Snow Cloak
EVs: 248 HP / 252 Special Defense / 8 Speed
Calm Nature (+SpD, -Atk)
Ice Beam
Water Pulse
Roost
Substitute
As you can see, this is my first team in a long time. So feel free to give any improvements!