This is a paid asset, but now you can download 2.5D Isometric engine for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
2.5D Isometric engine v1.3 (Latest version)
Shiva is a 2.5D isometric rendering engine that handles correct draw order using depth masks.
-Precise per-pixel draw order
-No artifacts, no manual cutting sprites
-Grid independent, not tight neither to hex nor rhombs
-Sprites react to light as if they were 3D
-Point light / Spotlight / Directional light
-Normal mapping for 3D Sprite illusion
-No semi-transparency issues
-Sprite tiling(repetitive background)
-Sprite atlas support
-No 3D, only flat 2D sprites
-Easy configuration – only 1 script