This is a paid asset, but now you can download Hand Painted Cave Pack 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.
For more detail this asset from the Unity Asset Store: Click Here
Hand Painted Cave Pack v1.1
“If possible, please buy the package to support the developer”
Update 1.1:
Removed all duplicated materials and animator components.
All meshes are lightmap enabled.
Added prefabs for easier level building.
Removed standard assets.
Compatible with unity 5!
Stylized assets to create your own fantasy cave or maze environment!
Videos:
Video walkthrough
Video walkthrough 2
Web demo:
Web demo
Features:
Includes an example scene and prefabs to get you started
Models range from 40 to 674 triangles.
Cave parts based on unity units (compatible with pro-grids)
Crystals, mushrooms with customizable colors.
Rocks, ferns, vases, ladders, carts, structures.
Particle effects, rainfall, torches, animated flags.