>>29950071In my opinion it's snorlax with body slam.
The next would either be lapras, or poliwrath with bubble, depending on their CP.
Dragnite's easy to take down with lapras, and treeman's pretty easy with a fire fang rk9.
The rest of the top gym mons you can cut through with grassmon like vileplume or victreebel.
Slowbro can be a bit annoying if he has psychic moves, and so can some vileplume and victreebel to a lesser extent if they have poison moves.
imo