Here’s a refined color palette with better contrasting pairs based on your original colors ( #5E99FF , #FF47A1 , #FFC93A , #FFFFFF ). I’ve made some adjustments for improved contrast and harmony.

 <Vibrant Contrast>
1. Sky Blue - 
                            
                            #0091EA
                         - A brighter blue that enhances contrast and maintains a fresh feel.
2. Hot Pink - 
                            
                            #FF2D55
                         - A more vivid pink that offers a striking contrast against the blue.
3. Golden Yellow - 
                            
                            #FFC107
                         - A warm golden yellow that provides a cheerful pop while ensuring readability.
4. Pure White - 
                            
                            #FFFFFF
                         - A clean white that enhances contrast and readability across the palette.
5. Deep Charcoal - 
                            
                            #333333
                         - A very dark shade that adds depth and works well against the lighter colors.

This updated palette maintains a vibrant and playful aesthetic while ensuring that each color stands out against the others, providing excellent contrast and usability.

Would you like any specific applications for this palette? Or do you have other color preferences in mind that you’d like to explore?