Documentação Vector icons:

https://github.com/oblador/react-native-vector-ico...

Android:

​project.ext.vectoricons = [
    iconFontNames: [ 'AntDesign.ttf', 'Feather.ttf', 'Ionicons.ttf', 'Entypo.ttf', 'MaterialCommunityIcons.ttf' ] // Name of the font files you want to copy
]

apply from: "../../node_modules/react-native-vector-icons/fonts.gradle"

iOS:

<key>UIAppFonts</key>
    <array>
    <string>AntDesign.ttf</string>
    <string>Entypo.ttf</string>
    <string>Feather.ttf</string>
    <string>Ionicons.ttf</string>
    <string>MaterialCommunityIcons.ttf</string>
    </array>