I have found a better way to organize Gradle files, it is useful for multi-module projects, where dependencies are duplicated. So instead of using a long list of implementations, we can group them into an array and import it as functions, here are the steps:

Step 1: Create a dependency.gradle file in your project level folder, in parallel with the project level build.gradle

Step 2: Import the settings in project level gradle

apply from: 'dependency.gradle'

buildscript {
    apply from: 'dependency.gradle'

    repositories {
        ...
    }
    dependencies {
        classpath classpaths.values()
    }
}

allprojects {
   ...
}

Step 3: Create the dependency.gradle file.

Note: the following is just an example, the actual gradle file is a lot longer

ext.versions = [
        versionCode       : 1,
        versionName       : "1.0.0",
        minVersion        : 21,
        targetVersion     : 27,
        compileVersion    : 27,
        appId             : "co.uk.yourappid",
        gradle            : "3.1.3",
        kotlinGradlePlugin: "1.2.41",
        googleServices    : "3.2.0",

        //android lib
        supportLibrary    : "27.1.1",
        constraintLayout  : "2.0.0-alpha1",
        kotlin            : "1.2.41",
        googleServices    : "3.2.0"

        //third party
        rxandroid         : "2.0.1",
        rxkotlin          : "2.1.0"
]

ext.classpaths = [
        gradle: "com.android.tools.build:gradle:$versions.gradle",
        gradleKotlin: "org.jetbrains.kotlin:kotlin-gradle-plugin:$versions.kotlinGradlePlugin",
        googleServices: "com.google.gms:google-services:$versions.googleServices"
]ext.files = [
        files: fileTree(dir: 'libs', include: ['*.jar'])
]ext.local = [
        tensorflow: project(':tensorflow'),
        mlkit     : project(':mlkit')
]

ext.androidLib = [
        kotlin       : "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$versions.kotlin",
        support4     : "com.android.support:support-v4:$versions.supportLibrary"
]

ext.daggerKapt = [
        daggerKapt       : "com.google.dagger:dagger-compiler:$versions.dagger",
        daggerAndroidKapt: "com.google.dagger:dagger-android-processor:$versions.dagger",
]

ext.daggerCompileOnly = [
        glassfishCompileOnly: "org.glassfish:javax.annotation:$versions.annotation"
]

Step 4: Add the dependencies into your module level gradle as function, and we can finally view the gradle file in one screen without scrolling up and down, hooray!

apply plugin: 'com.android.library'
...

android {
    compileSdkVersion versions.compileVersion
    defaultConfig {
        minSdkVersion versions.minSdkVersion
        targetSdkVersion targetSdkVersion
        ...}
}

dependencies {
    implementation files.values()
    implementation androidLib.values()
    implementation rxjava.values()
    implementation dagger.values()
    compileOnly daggerCompileOnly.values()
    kapt daggerKapt.values()
    implementation picasso.values()
    implementation mlkit.values()
}

You can find the full code here.