For more detail this asset from the Unity Asset Store: Click Here
This is a paid asset, but now you can download Tower Defense Level Kit for FREE, Please keep in mind this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Tower Defense Level Kit v1.0
This pack contains over 100 prefabs to construct your own Tower Defense Game, or MOBA evironnement.
You will find two types of towers (with 4 levels), 8 arms with 3 levels each, for a total of 192 possible combinations.
In addition a variety of plants, trees, rocks and various objects to decorate your map.
Low polygon modeling will also allow you to use it for mobile platforms.
Warning: the stage is real-time lighting to avoid huge package size
There is no script in this pack.