In Pokemon Sword & Shield you can encounter Pokemon in two different ways. ‘Overworld’ are the Pokemon you see physically walking around. ‘Non Overworld’ are random Pokemon hidden in grass and they are only revealed when starting a fight with them. This quick guide provides an overview of two types and explains the terminology.
Overworld Pokemon are physically seen walking around the world. You can tell from afar what Pokemon it is and you choose whether to engage in combat with it or run around it.
Non Overworld Pokemon are hidden in grass. It’s like in the old Pokemon games where you get a random Pokemon encounter as you walk through grass and you don’t know which one it will be. You will see an exclamation mark when a Pokemon has detected you (but physically visible Overworld Pokemon show the exclamation point, too!). The way you can tell it’s a Non-Overworld Pokemon is at the start of the fight it will have a black outline. Only after the fight starts the Pokemon is revealed. Each area is assigned a specific selection of Pokemon that can spawn (also depends on weather). Pokemon have different spawn chances – meaning some are rarer than others.
For a full list of All Pokemon Locations sorted by Habitat, please refer to: Pokemon Sword & Shield – All Pokemon Locations by Habitat.