Team GO Rocket Leader Guides
First Pokemon
Second Pokemon
Electivire, as a mono-Electric type, is only weak to Ground. Since most of its moves are Electric-type, that's a great choice! Keep in mind that it might hit you with Fighting-type damage, so any Steel- or Rock-types are risky!
Luxray, like Electivire, is mono-Electric, and is thus only weak to Ground. Snarl and Hidden Power don't hit very hard, so just use Ground-types.
Omastar has a double weakness to Grass, as well as a single weakness to Electric, Fighting, and Ground. While Ground is an easy choice since it's also good against Cliff's other slot 2 Pokémon, it does risk taking SE from Water Gun. As always, stay flexible!
Third Pokémon
Tyranitar is weak to Bug, Fairy, Grass, Ground, Steel, and Water, but you can mostly ignore those since Tyranitar is double weak to Fighting. Just bring out a Machamp, Lucario, Conkeldurr, Hariyama, Poliwrath, or even Obstagoon (Counter + Cross Chop) and you’ll do just fine! If those aren’t options, then you can start looking at other picks. Kyogre, Swampert, and Gyarados are probably the best Water-type choices. Excadrill (Mud Shot + Drill Run), Groudon (Mud Shot + Earthquake), and Metagross (Bullet Punch + Meteor Mash) can do really well too (though they struggle against Bite). But seriously: just punch it.
Charizard's cripplingly weak to Rock. It's hard to justify doing anything but.
Swampert is double weak to Grass, and that's its only weakness. Ergo...