get a rock type or a dark type

rock+steel -- aggron

dark+rock -- tyranitar(not in sapphire)(u shuld trade)

get an electric type to defeat wallace

remove machoke bcoz u already have balziken for fighting type

dusclops is defensive if u want offensive go for banette

Sableye. Its type combination allows it to be weak to nothing, and immune to Normal, Fighting, and Psychic. Also, if you can hack your game, give it Wonder Guard. Its an ability that makes only Super-Effective moves hit, but since Sableye has no weakness, nothing will hit it. This is a common hack Pokémon given the name WonderEye.

Use a Sharpedo! Fast and Strong!

Aggron or tyranitare...aggrons defence is great and tyranitar is strong but everything is super effective against it