<Yellow Excel Theme> 
1. Bright Yellow - 
                            
                            #FFEB3B
                         - A vibrant and eye-catching yellow that adds energy and positivity.
2. Soft Lemon - 
                            
                            #FFF9C4
                         - A light and soft yellow that provides a gentle background without overpowering.
3. Goldenrod - 
                            
                            #FFD54F
                         - A warm and inviting tone that adds a touch of sophistication.
4. Sunflower Yellow - 
                            
                            #FFC107
                         - A rich, sunflower-inspired yellow that is both cheerful and bright.
5. Pale Butter - 
                            
                            #FFF176
                         - A delicate, pale shade that serves as a subtle highlight.

This yellow color palette is designed to bring warmth and brightness to an Excel theme, ensuring that it is visually appealing while maintaining readability. The combination of vibrant and soft shades allows for a versatile application across various elements in the spreadsheet.

Would you like additional color options or suggestions for complementary colors?