Some good rock types that almost completely counter Charizard:
Tyranitar: With a Sp. Def boost due to sand and extra dynamax bulk, Tyranitar can take any attack Charizard throws at it. You can also throw on Weakness Policy on Tyranitar so that Max Rockfall can ensure a KO.
Drednaw (DMax): If you have a Swift Swim Drednaw and set up the rain before Charizard comes out with Max Geyser/Rain Dance, then a Max Geyser can completely wash away Charizard.
Coalossal (DMax or Gmax work): While it probably won't be activating Steam Engine, the only move Coalossal is really threatened by is Max Quake. Weakness Policy is more recommended on this one too because it isn't very strong, even when maxed.
Hope this helped!
Movesets for Listed Pokemon