Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download SciFi Base Pack 01 Free.
SciFi Base Pack 01 v02
Add a professional touch to your SciFi game project with those low poly models. Included in this package: 7 SciFi building blocks to create a Scifi base. Guns in defense towers can be rotated individually.
Included One unique Diffuse map for all the modular blocks (you can easily work on it to change colors, add your own stuffs etc), Normal map, Lights/Emissive map are also included.
Images format: jpeg. Included the Photoshop files in layers, you can customize colors, add your own logos etc. 4096×4096 px. texture can be easily be downsized as required.