Using application templates allows you to build applications faster because all the programming work has been done for you by the templates. All you need to do is build the application according to your customers’ needs. 
Below I will introduce you 20 templates worth using today
1. Universal Android App
The Universal Android App is one of the best and most popular Android apps available today. This great app allows users to create any application they want by taking unlimited content from sources such as blogs, timeline, feeds, channels, playlists or websites and easily Easily combine them into one customizable application. This template supports the most popular web content sources, like WordPress, YouTube, Facebook and RSS.
2. Material Design UI
Material Design UI is a cool and stylish Android UI template with five beautiful themes that can be used to make any app project you’re working on more aesthetically appealing. Sample topics aim to build social, travel, media and shopping apps and have a general theme that can be used with a variety of applications. This template uses hundreds of UI elements that can be combined to create a beautiful and unique application.
3. Universal Android WebView App
Transform your responsive and mobile web pages into a beautiful one using the Universal Android WebView App. It is compatible with WordPress and other web frameworks, is highly customizable and has many features and it supports HTML5, CSS3, JavaScript, jQuery, Bootstrap and other web technologies.
4. MaterialX
MaterialX is a UI template that can support any application project you want to develop. It is specifically designed to make your application look great by providing you with beautiful, ready-to-use documents, so no matter what application you are creating, you can do it. it’s in code. Features include grid, list and tab view, media player, social media timeline, ecommerce shopping, etc.
5. My Social Network
Integrated in Android Studio, My Social Network allows you to create your own personal social networking application, where you can publish posts, read posts from friends, chat privately with friends in the meantime. real time and more.
6. Dating App
Dating App will help you in creating your own online dating application. Built with Android Studio, the model’s notable features include a nice library and user profile. Users have the ability to comment, like, reply and send gifts, see potential dates nearby, make in-app purchases, send real-time direct messages with photos and of course they can block users. other.
7. WoWonder Android Messenger
Looking for a messenger application template to create your own Android messenger? Nothing else but the WoWonder Android Messenger application model. Specifically designed as an Android chat application for the WoWonder social network, WoWonder Mobile Messenger allows users to chat together on mobile phones. Features include the ability to make both audio and video calls, send and receive messages, share and upload photos, create audio recordings, and more.
8. The City
The City is a complex space and any app that helps locals and visitors navigate is bound. The city is a great application template for developers who want to create an app for their city with the most interesting attractions and best restaurants, cafes, bars, shops, etc.
All application data is stored in the local SQLite database, so the application works offline. The template has great features like MapView to display locations, featured categories for suggested locations, search filtering capabilities, saved search history and more.
9. Store Finder
Having an app to find a store on your mobile phone is indispensable. Store Finder has become popular among developers. Created with Android Studio and material design, the app has a long list of must-have features like email and SMS integration, user ratings and reviews, Google directions and media login. society. Users can also draw on maps, use map pins, share them on Facebook and Twitter, etc.
10. City Guide
Create your own handy travel guide for your chosen city using the City Guide Android application template. Developed in Android Studio and material design, this template is easy to configure and customize. It does not require programming skills to use.
You can organize the highlights of your chosen city into categories such as attractions, sports, hotels and nightlife. These selected highlights can also be considered clickable points on the interactive map using geolocation to determine the current location and distance on your phone from each highlight.
Refer
https://code.tutsplus.com/articles/15-best-android-app-templates-of-2017–cms-29643