Download demo: https://1drv.ms/u/s!AppH38QcoEBfiKU-QqN8sqtLCe1mrg
This asset includes a collection of 33 sprites with different types of circular gradients. Each type has three color versions. One that transitions from white to black, another that transitions from white to transparent, and a third that transitions from transparent to white. All sprites are 1024x1024 pixels large. In addition to this the asset includes the code that was used for generating the gradients, as well as a detailed guide explaining how to use the code to generate your own circular gradients (with custom color, size and gradient type).
Remember to read the asset's EULA: