Unity Tip #1: Color.HSVToRGB(h, s, v) produces smoother, more natural random colors than new Color(r, g, b)

ColorRotator.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ColorRotator : MonoBehaviour {

	public GameObject objHSV, objPlainColor;
	private Material objHSVMaterial, objPlainColorMaterial;
	private float timeDelta;

	private Rect rect = new Rect(10, 10, 0, 0);
	private readonly GUIContent guiContent = new GUIContent("HSV coloring on the left, RGB on the right.");
	private GUIStyleState guiStyleState;
	private GUIStyle guiStyle;

	// Use this for initialization
	void Start () {
		timeDelta = Random.value;
		objHSV.GetComponent<Renderer>().sharedMaterial = objHSVMaterial = (new Material(Shader.Find("Standard")));
		objPlainColor.GetComponent<Renderer>().sharedMaterial = objPlainColorMaterial = (new Material(Shader.Find("Standard")));

		guiStyleState = new GUIStyleState() { textColor = Color.magenta };
		guiStyle = new GUIStyle() { fontSize = 36, normal = guiStyleState };
	}

	private Color GetRandomHSVColor()
	{
		timeDelta += (Time.deltaTime / 100);
		float h = Mathf.PerlinNoise(0.5f, 23.3f * timeDelta);
		float s = Mathf.PerlinNoise(0.5f, 54.4f * timeDelta);
		float v = Mathf.PerlinNoise(0.5f, 12.6f * timeDelta);
		return Color.HSVToRGB(h, s, v);
	}

	private Color GetRandomColor()
	{
		float r = Mathf.PerlinNoise(0.5f, 23.3f * timeDelta);
		float g = Mathf.PerlinNoise(0.5f, 54.4f * timeDelta);
		float b = Mathf.PerlinNoise(0.5f, 12.6f * timeDelta);
		return new Color(r, g, b);
	}

	// Update is called once per frame
	void Update () {
		timeDelta += (Time.deltaTime / 100);
		objHSVMaterial.color = GetRandomHSVColor();
		objPlainColorMaterial.color = GetRandomColor();
	}

	private void OnGUI()
	{
		GUI.Label(rect, guiContent, guiStyle);
	}
}