I only saw one other person on the ladder who was actually using charizard. Well, there was that one guy using bellyzard, but I won't count that.
Wobbufett is an excellent partner for Charles, as he gets rid of scarfers that will come in afterwards to ruin your day. Solar power Zard...DOES NOT NEED NINETALES AS A PARTNER. You know how kingdra runs rain Dance on non weather teams to assist his sweeping? Charizard can do the same thing with sunny day. This is great for catching a Tyranitar or a politoed on the switch because, unlike sunny day ninetales, charizard can actually ko those Pokemon all by himself if no matter the build.
Seeing as how I always play sun, I was running a ninetales to support charizard anyway, while my charles was holding charcoal as an item and had a movement of sunny day, fire blast, solar beam, and focus blast.
Partners include rapid spinners and sr setters. Having sr down will allow you to take out dragonite with fire blast as well as some other bulky waters like tentacruel and such. Any spinner who isn't easily spin blocked and can handle one of chair's weaknesses is a fine choice. Hitmontop and donphan resists rock, while tentacruel resists water. The magic bouncers are alright too since you absolutely cannot allow rocks to hit the field when using this pokemon.
Against slower teams. Charley works alongside dual screen espeon a la heavy offense. Setting up sunny day with him behind screens is much easier than it sounds.