A 20-color eyeshadow palette with matte shades can offer a versatile range of colors for creating various makeup looks, from subtle and natural to bold and dramatic. Here's what you might expect from such a palette:

1. Color Range: Typically includes neutral tones like beige, brown, and taupe.

2. Pigmentation: High-quality matte eyeshadows should have strong pigmentation for vibrant color payoff.

3. Blend ability: Matte shades should be easy to blend, allowing for seamless transitions between colors.

4. Longevity: Long-lasting formula that stays put throughout the day without creasing or fading.

5. Texture: Smooth, non-chalky texture that applies evenly on the eyelid

6. Usage: Suitable for both everyday wear and special occasions, allowing for a variety of eye makeup looks.