Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download City Low Poly Free.
City Low Poly v3.0
171 different closed meshes for low poly buildings.
– Mixed atlased and tiling.
– All building materials are PBR with emission map.
– Average triangle count: 103
– Demo scene included.
v. 3.0 -> Updated all materials for PBR and added emission maps for all buildings.
v. 3.1 -> Updated for Unity 2019 URP
Warning: rooftops are a lot less detailed than external walls.