There are some interesting Pokémon in Pokémon Sword and Shield. An unusual creature you can encounter is Honedge, a Phantom and Steel-type floating sword Pokémon. If you want to add something unique to your list, this Honedge will make an excellent choice.
Unfortunately, you can only encounter this Pokémon in Heavy Fog. To run into Heavy Fog, you have the option to spawn after the sixth gym, but it is difficult to spawn in the game. However, after beating the game and heavy fog officially unlocks and you are more likely to spawn in the wilderness.
You have a fairly high chance of spawning Honedge in the Hammerlocke Hills in Heavy Fog, so you want to check out that location if you can roam there. You can also spot it as an exclamation point, but there's a bit more luck because you don't know what you come across until you fight it, and it only happens during a snowstorm in the same area.
At level 35, Honedge evolves into Doublade, remaining a Ghost and Steel type. If you want to bypass the minor evolution, you have the chance to encounter a Doublade on Outrage Lake during a snowstorm, but it only shows up in the grass as an exclamation point. Again, there are many possibilities.
The final evolution of Honedge is Aegislash Shield, which you can get after having a Doublade and give it a Twilight Stone. Stay as Ghost and Steel-type Pokémon.