According to the search results, Guzzlord is a Dark/Dragon-type Pokemon that is weak against Bug, Dragon, Fairy, Fighting, and Ice-type attacks. Fairy-type attacks deal quadruple damage to Guzzlord, making them the best option when battling it. If you dont have enough Fairy types to round out your team, you can also use Ice, Fighting, Bug, and other Dragon Pokemon. However, keep in mind that Dragon Pokemon will also take super-effective damage in return if Guzzlord knows a Dragon-type attack. Some recommended Pokemon and moves to use against Guzzlord include:

• Mega Gardevoir: Charm, Dazzling Gleam
• Shadow Gardevoir: Charm, Dazzling Gleam
• Xerneas: Geomancy, Moonblast
• Mega Rayquaza: Dragon Tail, Outrage
• Reshiram: Dragon Breath, Draco Meteor
• Garchomp: Dragon Tail, Outrage
• Togekiss: Charm, Dazzling Gleam
• Zacian: Quick Attack, Play Rough

It is recommended to team up with at least five other trainers and use a team of strong counters to defeat Guzzlord in a 5-Star Raid Battle. Once defeated, you will be given a limited amount of Premier Balls to attempt to catch it. You can use Razz Berries and throw Excellent Curve Balls to increase your chances of success.