Here’s a color palette based on your query for simple grey, green, blue, and orange. This palette features 6 harmonious colors that reflect a modern and clean aesthetic:

### Color Palette: "Calm and Bright"

1. **Soft Grey**
   - **Hex Code:** 
          
          #B0B3B8
       
   - **Description:** A light, neutral grey that serves as the foundation of the palette, offering a subtle backdrop that allows other colors to shine.

2. **Mint Green**
   - **Hex Code:** 
          
          #A8E6CF
       
   - **Description:** A refreshing and soft green that brings a sense of calm and tranquility, reminiscent of lush greenery.

3. **Sky Blue**
   - **Hex Code:** 
          
          #A4D7E1
       
   - **Description:** A gentle, airy blue that invokes a clear sky, adding a feeling of openness and serenity to the palette.

4. **Coral Orange**
   - **Hex Code:** 
          
          #FF6F61
       
   - **Description:** A vibrant coral orange that injects energy and warmth, serving as a cheerful accent to the more subdued tones.

5. **Charcoal Grey**
   - **Hex Code:** 
          
          #4A4A4A
       
   - **Description:** A deeper grey that provides contrast and depth, grounding the palette and adding sophistication.

6. **Turquoise Blue**
   - **Hex Code:** 
          
          #30B0C7
       
   - **Description:** A bright turquoise that adds a pop of color, reminiscent of tropical waters, creating a lively and inviting atmosphere.

### Palette Overview:
This color palette combines muted tones with vibrant accents, creating a balanced and versatile selection that can be used in various design applications, from branding to interior design. The soft greys and greens evoke feelings of calmness, while the blues and oranges add a touch of liveliness, making it suitable for both modern and playful designs.