However, you could use these options, depending on the context:
* A burst of sun rays: This emphasizes the sudden and intense nature of the rays.
* A shower of sun rays: This evokes a gentle, light feeling.
* A beam of sun rays: This emphasizes the straight, concentrated lines of light.
* A halo of sun rays: This emphasizes the circular and radiant shape of the rays, especially around the sun.
You could also describe them as a shaft of sunlight, a stream of light, or a blaze of glory.
Ultimately, the best collective noun to use depends on the specific image or feeling you want to convey.