Ducklett debuts on Pokémon Go during the weekly challenges of Pokémon Go Fest 2020 and can be found in the wild. You should be able to find it by wandering around your neighborhood or hatching 5-mile-long eggs. When you catch enough, you can evolve it into Swanna. He can learn several moves, but you want to make sure you keep one with the best choices.
Swanna is a Water and Flying type Pokémon. It will have a maximum CP of 2.088 and an attack of 182, a defense of 132 and a stamina of 181. Unfortunately, due to its CP, you probably won't want to use it in the Ultra League, but it could be a viable option for the Grand League. if you don't try to boost it beyond 1.500 CP. It's just for the Electric-type and Rock-type bindings, which might give it a little edge when you think about your list. You wouldn't want to have Swanna as your first Pokémon, but it would be a good backup choice to rotate into after the first fight.
The best moveset available for Swanna includes water pistol and bubble beam, or water pistol and hurricane. The first option involves using two Water-type attacks which are useful if you primarily want to use Swanna as a means of countering Ground, Rock and Fire. But since he's also a Flying-type, you should maximize all the benefits of his status-type bonus attack moves, so the water pistol and hurricane are a better combination. The combination of water pistol and bubble beam would work exceptionally well for lower tier raids.