Resists Rock, Ice, Electric, Psychic, Ghost, Bug, and Dark Needs to be NU or below Does not need weather to work well
No Pokemon resist all of those but one Pokemon that first comes to my mind is Bastiodon a Rock/Steel Type.
>Bastiodon (M) @ Leftovers Trait: Sturdy EVs: 252 HP / 4 Def / 252 SDef Careful Nature (+SDef, -SAtk) - Metal Burst - Protect - Stealth Rock - Roar
-Mew
There is nothing below the NU tier; NU means Neverused, so there isn't a tier that's lower than that.
Bastiodon (Rock/ Steel) Mawile (Steel) Probopass (Rock/ Steel)
They don't resist Electric, but are neutral to it.