マテリアルデザインの色を選んでアプリのテーマカラーを選択できるサイト( https://material.io/color/ )を見ていてここの色一覧が欲しいと思って調べたらすでに作ってくれている人がいました。
そこでマテリアルデザインカラーのXMLをカラーパレットとしてvaluesに定義しておくと便利だったので紹介します。

メリット

これをカラーパレットとして使うことでアプリで利用する色を統一できる。
特定の色のカラーコードをわざわざ調べなくてもよくなる

デメリット

未使用のcolor定義が増える。

使用例

後述のXMLをcolor_palettes.xmlとして用意して、colors.xmlからcolor_palettes.xmlに定義した色を参照する。

colors.xml

    <color name="colorPrimary">@color/md_red_400</color>
    <color name="colorPrimaryDark">@color/md_red_500</color>
    <color name="colorAccent">@color/md_blue_400</color>

マテリアルデザインカラーのXML

https://gist.github.com/daniellevass/b0b8cfa773488e138037 から転載（2017/08/18時点）

color_palettes.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

<!-- google's material design colours from 
http://www.google.com/design/spec/style/color.html#color-ui-color-palette -->

    <!--reds-->
    <color name="md_red_50">#FFEBEE</color>
    <color name="md_red_100">#FFCDD2</color>
    <color name="md_red_200">#EF9A9A</color>
    <color name="md_red_300">#E57373</color>
    <color name="md_red_400">#EF5350</color>
    <color name="md_red_500">#F44336</color>
    <color name="md_red_600">#E53935</color>
    <color name="md_red_700">#D32F2F</color>
    <color name="md_red_800">#C62828</color>
    <color name="md_red_900">#B71C1C</color>
    <color name="md_red_A100">#FF8A80</color>
    <color name="md_red_A200">#FF5252</color>
    <color name="md_red_A400">#FF1744</color>
    <color name="md_red_A700">#D50000</color>

    <!-- pinks -->
    <color name="md_pink_50">#FCE4EC</color>
    <color name="md_pink_100">#F8BBD0</color>
    <color name="md_pink_200">#F48FB1</color>
    <color name="md_pink_300">#F06292</color>
    <color name="md_pink_400">#EC407A</color>
    <color name="md_pink_500">#E91E63</color>
    <color name="md_pink_600">#D81B60</color>
    <color name="md_pink_700">#C2185B</color>
    <color name="md_pink_800">#AD1457</color>
    <color name="md_pink_900">#880E4F</color>
    <color name="md_pink_A100">#FF80AB</color>
    <color name="md_pink_A200">#FF4081</color>
    <color name="md_pink_A400">#F50057</color>
    <color name="md_pink_A700">#C51162</color>

    <!-- purples -->
    <color name="md_purple_50">#F3E5F5</color>
    <color name="md_purple_100">#E1BEE7</color>
    <color name="md_purple_200">#CE93D8</color>
    <color name="md_purple_300">#BA68C8</color>
    <color name="md_purple_400">#AB47BC</color>
    <color name="md_purple_500">#9C27B0</color>
    <color name="md_purple_600">#8E24AA</color>
    <color name="md_purple_700">#7B1FA2</color>
    <color name="md_purple_800">#6A1B9A</color>
    <color name="md_purple_900">#4A148C</color>
    <color name="md_purple_A100">#EA80FC</color>
    <color name="md_purple_A200">#E040FB</color>
    <color name="md_purple_A400">#D500F9</color>
    <color name="md_purple_A700">#AA00FF</color>

    <!-- deep purples -->
    <color name="md_deep_purple_50">#EDE7F6</color>
    <color name="md_deep_purple_100">#D1C4E9</color>
    <color name="md_deep_purple_200">#B39DDB</color>
    <color name="md_deep_purple_300">#9575CD</color>
    <color name="md_deep_purple_400">#7E57C2</color>
    <color name="md_deep_purple_500">#673AB7</color>
    <color name="md_deep_purple_600">#5E35B1</color>
    <color name="md_deep_purple_700">#512DA8</color>
    <color name="md_deep_purple_800">#4527A0</color>
    <color name="md_deep_purple_900">#311B92</color>
    <color name="md_deep_purple_A100">#B388FF</color>
    <color name="md_deep_purple_A200">#7C4DFF</color>
    <color name="md_deep_purple_A400">#651FFF</color>
    <color name="md_deep_purple_A700">#6200EA</color>

    <!-- indigo -->
    <color name="md_indigo_50">#E8EAF6</color>
    <color name="md_indigo_100">#C5CAE9</color>
    <color name="md_indigo_200">#9FA8DA</color>
    <color name="md_indigo_300">#7986CB</color>
    <color name="md_indigo_400">#5C6BC0</color>
    <color name="md_indigo_500">#3F51B5</color>
    <color name="md_indigo_600">#3949AB</color>
    <color name="md_indigo_700">#303F9F</color>
    <color name="md_indigo_800">#283593</color>
    <color name="md_indigo_900">#1A237E</color>
    <color name="md_indigo_A100">#8C9EFF</color>
    <color name="md_indigo_A200">#536DFE</color>
    <color name="md_indigo_A400">#3D5AFE</color>
    <color name="md_indigo_A700">#304FFE</color>

    <!--blue-->
    <color name="md_blue_50">#E3F2FD</color>
    <color name="md_blue_100">#BBDEFB</color>
    <color name="md_blue_200">#90CAF9</color>
    <color name="md_blue_300">#64B5F6</color>
    <color name="md_blue_400">#42A5F5</color>
    <color name="md_blue_500">#2196F3</color>
    <color name="md_blue_600">#1E88E5</color>
    <color name="md_blue_700">#1976D2</color>
    <color name="md_blue_800">#1565C0</color>
    <color name="md_blue_900">#0D47A1</color>
    <color name="md_blue_A100">#82B1FF</color>
    <color name="md_blue_A200">#448AFF</color>
    <color name="md_blue_A400">#2979FF</color>
    <color name="md_blue_A700">#2962FF</color>

    <!-- light blue-->
    <color name="md_light_blue_50">#E1F5FE</color>
    <color name="md_light_blue_100">#B3E5FC</color>
    <color name="md_light_blue_200">#81D4fA</color>
    <color name="md_light_blue_300">#4fC3F7</color>
    <color name="md_light_blue_400">#29B6FC</color>
    <color name="md_light_blue_500">#03A9F4</color>
    <color name="md_light_blue_600">#039BE5</color>
    <color name="md_light_blue_700">#0288D1</color>
    <color name="md_light_blue_800">#0277BD</color>
    <color name="md_light_blue_900">#01579B</color>
    <color name="md_light_blue_A100">#80D8FF</color>
    <color name="md_light_blue_A200">#40C4FF</color>
    <color name="md_light_blue_A400">#00B0FF</color>
    <color name="md_light_blue_A700">#0091EA</color>

    <!-- cyan -->
    <color name="md_cyan_50">#E0F7FA</color>
    <color name="md_cyan_100">#B2EBF2</color>
    <color name="md_cyan_200">#80DEEA</color>
    <color name="md_cyan_300">#4DD0E1</color>
    <color name="md_cyan_400">#26C6DA</color>
    <color name="md_cyan_500">#00BCD4</color>
    <color name="md_cyan_600">#00ACC1</color>
    <color name="md_cyan_700">#0097A7</color>
    <color name="md_cyan_800">#00838F</color>
    <color name="md_cyan_900">#006064</color>
    <color name="md_cyan_A100">#84FFFF</color>
    <color name="md_cyan_A200">#18FFFF</color>
    <color name="md_cyan_A400">#00E5FF</color>
    <color name="md_cyan_A700">#00B8D4</color>

    <!-- teal -->
    <color name="md_teal_50">#E0F2F1</color>
    <color name="md_teal_100">#B2DFDB</color>
    <color name="md_teal_200">#80CBC4</color>
    <color name="md_teal_300">#4DB6AC</color>
    <color name="md_teal_400">#26A69A</color>
    <color name="md_teal_500">#009688</color>
    <color name="md_teal_600">#00897B</color>
    <color name="md_teal_700">#00796B</color>
    <color name="md_teal_800">#00695C</color>
    <color name="md_teal_900">#004D40</color>
    <color name="md_teal_A100">#A7FFEB</color>
    <color name="md_teal_A200">#64FFDA</color>
    <color name="md_teal_A400">#1DE9B6</color>
    <color name="md_teal_A700">#00BFA5</color>

    <!-- green -->
    <color name="md_green_50">#E8F5E9</color>
    <color name="md_green_100">#C8E6C9</color>
    <color name="md_green_200">#A5D6A7</color>
    <color name="md_green_300">#81C784</color>
    <color name="md_green_400">#66BB6A</color>
    <color name="md_green_500">#4CAF50</color>
    <color name="md_green_600">#43A047</color>
    <color name="md_green_700">#388E3C</color>
    <color name="md_green_800">#2E7D32</color>
    <color name="md_green_900">#1B5E20</color>
    <color name="md_green_A100">#B9F6CA</color>
    <color name="md_green_A200">#69F0AE</color>
    <color name="md_green_A400">#00E676</color>
    <color name="md_green_A700">#00C853</color>

    <!--light green-->
    <color name="md_light_green_50">#F1F8E9</color>
    <color name="md_light_green_100">#DCEDC8</color>
    <color name="md_light_green_200">#C5E1A5</color>
    <color name="md_light_green_300">#AED581</color>
    <color name="md_light_green_400">#9CCC65</color>
    <color name="md_light_green_500">#8BC34A</color>
    <color name="md_light_green_600">#7CB342</color>
    <color name="md_light_green_700">#689F38</color>
    <color name="md_light_green_800">#558B2F</color>
    <color name="md_light_green_900">#33691E</color>
    <color name="md_light_green_A100">#CCFF90</color>
    <color name="md_light_green_A200">#B2FF59</color>
    <color name="md_light_green_A400">#76FF03</color>
    <color name="md_light_green_A700">#64DD17</color>

    <!-- lime-->
    <color name="md_lime_50">#F9FBE7</color>
    <color name="md_lime_100">#F0F4C3</color>
    <color name="md_lime_200">#E6EE9C</color>
    <color name="md_lime_300">#DCE775</color>
    <color name="md_lime_400">#D4E157</color>
    <color name="md_lime_500">#CDDC39</color>
    <color name="md_lime_600">#C0CA33</color>
    <color name="md_lime_700">#A4B42B</color>
    <color name="md_lime_800">#9E9D24</color>
    <color name="md_lime_900">#827717</color>
    <color name="md_lime_A100">#F4FF81</color>
    <color name="md_lime_A200">#EEFF41</color>
    <color name="md_lime_A400">#C6FF00</color>
    <color name="md_lime_A700">#AEEA00</color>

    <!--yellow -->
    <color name="md_yellow_50">#FFFDE7</color>
    <color name="md_yellow_100">#FFF9C4</color>
    <color name="md_yellow_200">#FFF590</color>
    <color name="md_yellow_300">#FFF176</color>
    <color name="md_yellow_400">#FFEE58</color>
    <color name="md_yellow_500">#FFEB3B</color>
    <color name="md_yellow_600">#FDD835</color>
    <color name="md_yellow_700">#FBC02D</color>
    <color name="md_yellow_800">#F9A825</color>
    <color name="md_yellow_900">#F57F17</color>
    <color name="md_yellow_A100">#FFFF82</color>
    <color name="md_yellow_A200">#FFFF00</color>
    <color name="md_yellow_A400">#FFEA00</color>
    <color name="md_yellow_A700">#FFD600</color>

    <!--amber-->
    <color name="md_amber_50">#FFF8E1</color>
    <color name="md_amber_100">#FFECB3</color>
    <color name="md_amber_200">#FFE082</color>
    <color name="md_amber_300">#FFD54F</color>
    <color name="md_amber_400">#FFCA28</color>
    <color name="md_amber_500">#FFC107</color>
    <color name="md_amber_600">#FFB300</color>
    <color name="md_amber_700">#FFA000</color>
    <color name="md_amber_800">#FF8F00</color>
    <color name="md_amber_900">#FF6F00</color>
    <color name="md_amber_A100">#FFE57F</color>
    <color name="md_amber_A200">#FFD740</color>
    <color name="md_amber_A400">#FFC400</color>
    <color name="md_amber_A700">#FFAB00</color>

    <!--orange-->
    <color name="md_orange_50">#FFF3E0</color>
    <color name="md_orange_100">#FFE0B2</color>
    <color name="md_orange_200">#FFCC80</color>
    <color name="md_orange_300">#FFB74D</color>
    <color name="md_orange_400">#FFA726</color>
    <color name="md_orange_500">#FF9800</color>
    <color name="md_orange_600">#FB8C00</color>
    <color name="md_orange_700">#F57C00</color>
    <color name="md_orange_800">#EF6C00</color>
    <color name="md_orange_900">#E65100</color>
    <color name="md_orange_A100">#FFD180</color>
    <color name="md_orange_A200">#FFAB40</color>
    <color name="md_orange_A400">#FF9100</color>
    <color name="md_orange_A700">#FF6D00</color>

    <!--deep orange-->
    <color name="md_deep_orange_50">#FBE9A7</color>
    <color name="md_deep_orange_100">#FFCCBC</color>
    <color name="md_deep_orange_200">#FFAB91</color>
    <color name="md_deep_orange_300">#FF8A65</color>
    <color name="md_deep_orange_400">#FF7043</color>
    <color name="md_deep_orange_500">#FF5722</color>
    <color name="md_deep_orange_600">#F4511E</color>
    <color name="md_deep_orange_700">#E64A19</color>
    <color name="md_deep_orange_800">#D84315</color>
    <color name="md_deep_orange_900">#BF360C</color>
    <color name="md_deep_orange_A100">#FF9E80</color>
    <color name="md_deep_orange_A200">#FF6E40</color>
    <color name="md_deep_orange_A400">#FF3D00</color>
    <color name="md_deep_orange_A700">#DD2600</color>

    <!--brown -->
    <color name="md_brown_50">#EFEBE9</color>
    <color name="md_brown_100">#D7CCC8</color>
    <color name="md_brown_200">#BCAAA4</color>
    <color name="md_brown_300">#A1887F</color>
    <color name="md_brown_400">#8D6E63</color>
    <color name="md_brown_500">#795548</color>
    <color name="md_brown_600">#6D4C41</color>
    <color name="md_brown_700">#5D4037</color>
    <color name="md_brown_800">#4E342E</color>
    <color name="md_brown_900">#3E2723</color>

    <!--grey-->
    <color name="md_grey_50">#FAFAFA</color>
    <color name="md_grey_100">#F5F5F5</color>
    <color name="md_grey_200">#EEEEEE</color>
    <color name="md_grey_300">#E0E0E0</color>
    <color name="md_grey_400">#BDBDBD</color>
    <color name="md_grey_500">#9E9E9E</color>
    <color name="md_grey_600">#757575</color>
    <color name="md_grey_700">#616161</color>
    <color name="md_grey_800">#424242</color>
    <color name="md_grey_900">#212121</color>
    <color name="md_black_1000">#000000</color>
    <color name="md_white_1000">#ffffff</color>

    <!--blue grey-->
    <color name="md_blue_grey_50">#ECEFF1</color>
    <color name="md_blue_grey_100">#CFD8DC</color>
    <color name="md_blue_grey_200">#B0BBC5</color>
    <color name="md_blue_grey_300">#90A4AE</color>
    <color name="md_blue_grey_400">#78909C</color>
    <color name="md_blue_grey_500">#607D8B</color>
    <color name="md_blue_grey_600">#546E7A</color>
    <color name="md_blue_grey_700">#455A64</color>
    <color name="md_blue_grey_800">#37474F</color>
    <color name="md_blue_grey_900">#263238</color>
    
</resources>

参考

Color Tool - Material Design
https://material.io/color/#!/

Android Material Design Colours
https://gist.github.com/daniellevass/b0b8cfa773488e138037

Color - Style - Material design guidelines
https://material.io/guidelines/style/color.html