Simple View represents common UI System Colors for iOS and macOS.

ExampleColorSchemes.swift

import SwiftUI
#if os(iOS)
import UIKit
#endif

/**
Display a simple view of the common system colors used for interface design. Quick reference that if in Canvas will display in a larger format.
*/
struct ExampleColorSchemes: View {

    var isPreviewWindow = false
    
    let columns = [GridItem(.adaptive(minimum: 140))]

    var body: some View {
        ScrollView {
            LazyVGrid(columns: columns, spacing: 12) {
                ForEach(ColorSection.allCases, id: \.self) { section in
                    Section(header: Text(section.rawValue).font(.title2).bold().padding()) {
                        ForEach(section.colors, id: \.self) { color in
                            VStack(alignment: .center, spacing: 0) {
                                Spacer()
                                Text(color.debugDescription.replacingOccurrences(of: "Catalog color: System ", with: ""))
                                    .lineLimit(2)
                                    .multilineTextAlignment(.center)
                                    .fontWeight(.ultraLight)
                                    .minimumScaleFactor(0.8)
                                    .padding([.horizontal, .bottom],6)
                                Rectangle()
                                    .fill(Color(color))
                                    .frame(height: 50)
                                    .cornerRadius(10)
                            }
                            .frame(width: 140)
                            .overlay(RoundedRectangle(cornerRadius: 10).stroke(Color.white, lineWidth: 0.4))
                        }
                    }
                }
            }
            .padding()
            LazyVGrid(columns: columns) {
                ForEach(ColorNames.allCases, id: \.self) { color in
                    VStack(alignment: .leading) {
                        Text(color.rawValue)
                            .frame(width: 80, alignment: .leading)
                        Rectangle()
                            .fill(color.color)
                            .frame(width: 50, height: 50)
                            .border(Color.black)
                    }
                }
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)
            .padding()
        }
        .frame(width: isPreviewWindow ? 800 : nil, height:isPreviewWindow ? 2000 : nil)
    }

  
}

#if os(iOS)
enum ColorSection: String, CaseIterable {
    case label = "Label Colors"
    case fill = "Fill Colors"
    case text = "Text Colors"
    case tint = "Tint Colors"
    case standardBackground = "Standard Background Colors"
    case groupedBackground = "Grouped Background Colors"
    case separator = "Separator Colors"
    case link = "Link Colors"
    case nonAdaptable = "Non-Adaptable Colors"
    
    var colors: [UIColor] {
        switch self {
        case .label:
            return [UIColor.label, UIColor.secondaryLabel, UIColor.tertiaryLabel, UIColor.quaternaryLabel]
        case .fill:
            return [UIColor.systemFill, UIColor.secondarySystemFill, UIColor.tertiarySystemFill, UIColor.quaternarySystemFill]
        case .text:
            return [UIColor.placeholderText]
        case .tint:
            return [UIColor.tintColor]
        case .standardBackground:
            return [UIColor.systemBackground, UIColor.secondarySystemBackground, UIColor.tertiarySystemBackground]
        case .groupedBackground:
            return [UIColor.systemGroupedBackground, UIColor.secondarySystemGroupedBackground, UIColor.tertiarySystemGroupedBackground]
        case .separator:
            return [UIColor.separator, UIColor.opaqueSeparator]
        case .link:
            return [UIColor.link]
        case .nonAdaptable:
            return [UIColor.darkText, UIColor.lightText]
        }
    }
}
#elseif os(macOS)


enum ColorSection: String, CaseIterable {
    case label = "Label Colors"
    case text = "Text Colors"
    case content = "Content Colors"
    case menu = "Menu Colors"
    case table = "Table Colors"
    case control = "Control Colors"
    case window = "Window Colors"
    case highlightsAndShadows = "Highlights and Shadows"
    
    var colors: [NSColor] {
        switch self {
        case .label:
            return [NSColor.labelColor, NSColor.secondaryLabelColor, NSColor.tertiaryLabelColor, NSColor.quaternaryLabelColor]
        case .text:
            return [NSColor.textColor, NSColor.placeholderTextColor, NSColor.selectedTextColor, NSColor.textBackgroundColor, NSColor.selectedTextBackgroundColor, NSColor.keyboardFocusIndicatorColor, NSColor.unemphasizedSelectedTextColor, NSColor.unemphasizedSelectedTextBackgroundColor]
        case .content:
            return [NSColor.linkColor, NSColor.separatorColor, NSColor.selectedContentBackgroundColor, NSColor.unemphasizedSelectedContentBackgroundColor]
        case .menu:
            return [NSColor.selectedMenuItemTextColor]
        case .table:
            return [NSColor.gridColor, NSColor.headerTextColor]
        case .control:
            return [NSColor.controlAccentColor, NSColor.controlColor, NSColor.controlBackgroundColor, NSColor.controlTextColor, NSColor.disabledControlTextColor, NSColor.selectedControlColor, NSColor.selectedControlTextColor, NSColor.alternateSelectedControlTextColor, NSColor.scrubberTexturedBackground]
        case .window:
            return [NSColor.windowBackgroundColor, NSColor.windowFrameTextColor, NSColor.underPageBackgroundColor]
        case .highlightsAndShadows:
            return [NSColor.findHighlightColor, NSColor.highlightColor, NSColor.shadowColor]
        }
    }
}
#endif


//SwiftUI Colors
enum ColorNames: String, CaseIterable {
    case black
    case blue
    case brown
    case clear
    case cyan
    case gray
    case green
    case indigo
    case mint
    case orange
    case pink
    case purple
    case red
    case teal
    case white
    case yellow
    case accentColor
    case primary
    case secondary
    case tertiary
    
    var color: Color {
           switch self {
           case .black: return Color.black
           case .blue: return Color.blue
           case .brown: return Color.brown
           case .clear: return Color.clear
           case .cyan: return Color.cyan
           case .gray: return Color.gray
           case .green: return Color.green
           case .indigo: return Color.indigo
           case .mint: return Color.mint
           case .orange: return Color.orange
           case .pink: return Color.pink
           case .purple: return Color.purple
           case .red: return Color.red
           case .teal: return Color.teal
           case .white: return Color.white
           case .yellow: return Color.yellow
           case .accentColor: return Color.accentColor
           case .primary: return Color.primary
           case .secondary: return Color.secondary
#if os(macOS)
           case .tertiary: return Color(NSColor.tertiaryLabelColor)
#endif
           }
       }
    
}


struct ExampleColorSchemes_Previews: PreviewProvider {
    static var previews: some View {
        ExampleColorSchemes(isPreviewWindow: true)
    }
}