This is a paid asset, but now you can download PolyWorld: Low Poly Vistas Free.
Detail this asset from Unity Store: Original Link
PolyWorld: Low Poly Vistas v1.01
PolyWorld: Vistas is a collection of low-poly-style meshes to be used to enhance your PolyWorld scenes.
If you like this, be sure to take a look at the other PolyWorld Packs
– Mesh sets in 5 biomes: Snowy Sylvan,Dry, Icebergs, Volcanic, Sandy Cliffs.
– 14 faceted skyboxes to give you a variety of lighting conditions.
– Unparalled support via email.
*PolyWorld scripts not included.