What are the best Pokemon to attack or defend gyms?

After the gym system was overhauled, it became a lot more fun to play Pokémon Go with friends. With the release of legendaries in raid battles, it's really important that you know which Pokemon are good to use in gyms. Even more so now that Pokémon Go accepts legendaries. See the best for attacking or defending gyms.

Don't forget to also see the best Pokémon in the game in general.

The best Pokemon to attack gyms

We will use as a basis the analysis of the specialized website GamePress, which simulates various game scenarios to list the best ones. See the ones at the top followed by the best attacks:

1. Tyranitar (Bite with Crunch or Stone Edge)
2. Dragonite (Dragon Tail ou Dragon Breath com Outrage ou Hurricane)
3. machamp (Counter ou Karate Chop com Dynamic Punch)
4. G (Rock Throw, Mud Slap ou Mud Shop com Rock Blast ou Earthquake)
5. Omastar (Rock Throw com Rock Slide ou Rock Blast)
6. Rhydon (Mud Slap com Earthquake)
7. Vaporeon (Water Gun com Hydro Pump ou Aqua Tail)
8. Espeon (Confusion ou Zen Headbutt com Future Sight)
9. exeggutor (Confusion, Extrasensory ou Bullet Seed com Solar Beam)
10. Alakazam (Confusion ou Psycho Cut com Future Sight)

Until the last update of this post, GamePress did not include the legendaries in the comparison.

The best Pokemon to defend gyms

So far, it is not possible to use a Legendary Pokémon to defend a Gym. Here are the best Pokémon to defend gyms:

1. Blissey (Zen Headbutt ou Pound com Dazzling Gleam)
2. Snorlax (Zen Headbutt com Heavy Slam ou Body Slam)
3. Chansey (Zen Headbutt com Dazzling Gleam)
4. Lapras (Ice Shard ou Frost Breath com Ice Beam, Blizzard ou Hydro Pump)
5. Steelix (Dragon Tail com Crunch ou Heavy Slam)
6. Muk (Infestation or Poison Jab with Dark Pulse)
7. Dragonite (Dragon Tail com Dragon Claw, Outrage ou Hurricane)
8. gyrados (Dragon Tail com Hydro Pump, Outrage, Crunch ou Twister)
9. Slowking (Confusion com Fire Blast, Blizzard ou Psychic)
10. Ampharos (Volt Switch com Focus Blast ou Thunder)