Before there were Legendary Pokemon in Pokemon Go, Dragonite was hands down the best Pokemon overall. In terms of stats, he was the overall highest. Even now, he is undoubtably one of the best pokemon.
Tips and strategies
Recommended attack types
Dragonite being a Dual Dragon/Flying-type Pokemon has 4 weaknesses namely Ice, Rock, Dragon and Fairy. Use these types of attacks to gain an advantage during battle. On the other hand, Avoid using Bug, Fighting, Fire, Water or Grass-type moves against Dragonite as he is resistant to these types of attacks.
Ice-type is super effective!
Ice-type attacks are the best when dealing with Dragonite as they are a double super effective. A pokemon with Ice beam or Blizzard could quickly turn the battle in your favor.
Dragonite's attacks are mostly Dragon-type can only be resisted by Steel or Fairy-type Pokemon. Fairy is recommended as it will also deal super effective damage.