I suppose Poison pollutes it, never though of that.
Psychic is used on few Pokemon, other than say Azelf. It is generally only used as STAB. It is an inferior attacking type.
The best attacking types are Fighting, Ice, Dragon, Water and, best of all, Ground.
Fighting and Ground are super effective against the most types with Ice coming at a close second.
Water and Dragon aren't resisted by much (Empoleon). Water is better defensively though.
I believe you forgot Fire on this list, although Fire is not the best attacking type in terms of SE coverage, it hits Steels super effectively which is an extremely important asset to any team.