For Unity 2019.3+ | URP | HDRP | Built-in
Underwater
The Underwater effect creates waves that distort the image and adds a colored water fog.
This effect works best when the far clipping plane of the camera is set to a smaller value, such that the entire scene just about fits within the camera.
This effect requires the Bump Map to be set in order to work properly. An example is provided at Resources/Textures/UnderwaterNormals.png.