Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download Sci-fi Factory Modular Kitbash Free.
Sci-fi Factory Modular Kit v1.0
More than 60 models to create your own prefabs and game objects
Small size – good for web and mobile games
USES ONLY ONE ATLAS 2048 * 1024!!!
+ very realistic and efficient shader lava and smoke