Soft Gradient effects

What do you guys call this type of shader or effects? How can achieve this?soft-color-gradient-background-holographic-vector-19928266

I would say it’s a multicolor gradient^^.

Well, one way to achieve this one the fly with shaders is by mixing colors with the GLSL build-in function mix. It essentially performs a linear interpolation between two values (e.g. colors).

Live demo:

Of course you can combine multiple calls of mix in order to involve more colors into your effect.