If you are looking to complete your Pokédex in Pokémon Sword and Shield, you need to spend some time exploring the Galar region. Fortunately, you can find most of the Pokémon in the wild area, just outside of Motostoke and Hammerlocke. One particularly difficult Pokémon to spot is Larvitar, which you must evolve into a Tyranitar. However, it has a fixed spawn position.
You can find this Pokémon in the wild area, and you can access it when you get the Rotom Bicycle upgrade to cross the water. When you have this, proceed to the Wild Area just outside Hammerlocke and go west to Outrage Lake. You can find Larvitar on the other side.
Unfortunately, you won't see them in the afterlife. It only shows up as exclamation marks in the grass, so you need to explore the wilderness thoroughly to have a fair chance of spotting one. You also only have a five percent chance of finding it. You need to make sure that the weather conditions are cloudy or intense sunshine.
If you want a little more luck, you can find Larvitar's evolved form, Pupitar, in the same area, and it has a chance to appear in the afterlife. Relying on the search for a Pupitar before finding a Larvitar is not the best approach because you have a better chance of identifying the first evolution. You can find a Pupitar during a sandstorm, so they spawn in different weather conditions.
When you discover your Larvitar or Pupitar, make sure you don't use a Grass or Water type as you don't want to pass out completely when you engage it. They are both Ground and Rock type Pokémon.
A Larvitar evolves into a Pupitar at level 30, then becomes a Tyranitar at level 55, which is a Rock and Dark type Pokémon.