Ghost and dark are the best ones. Physics don't do much damage against steel so steel types have an edge too.
Or you can use a Bug-pokemon that is not dualized as bug/poison.
If you have Mewtwo and teaches him Ghost ball, it'll be good too. Then mewtwo will only take half the dmg, and he will do 2 x dmg.
Grass, Flying and Rock types.
Ground types and psychic types beat poison types.
Dragon and Ice Types
electric and grass types
Quagasire is pathetic against grass types, so yeah.
ghost and bug
they get hurt by dragon types.Some get hurt by water or pysic types.
There are three types of heart rhythms and they include; Supraventricular arrhythmias,Ventricular arrhythmias,Bradyarrhythmias.
Grass, Flying and Rock types.
Ground types and psychic types beat poison types.
What beats Fighting types easily are Psychic, and Flying.
Rock, or Ice types.
Ground Types work the greatest.
grass types
Dragon and Ice Types
In Pokemon certain types can beat others and here are my examples: Water beats Fire, Fire beats Grass, Grass beats Water, Dark beats Ghost, Water beats Electric, Water beats Ground, Water beats Rock, Grass beats Rock, Grass beats Ground, Fighting beats Grass, Flying beats Grass, Physic can beat Grass, Ground beats Fire, Fire beats Steel, Fighting beats Dark, Bug beats Dark
electric and grass types