At the moment you need to create your own.
In the latest blog post about the K12 Service Pack (planned to be released in June) there is a note about more ready to use inline editors:
https://www.kentico.com/blog/kentico-12-service-pack-news
Therefore, along with the Kentico 12 Service Pack’s release, we will also provide you with a range of selectors ready for your MVC projects so you can develop faster.
Since this feature is quite new not much examples are available, but give it time and the community will be able to supply more and more examples!
Check out this recent blog about set it up using Vue.js
https://medium.com/js-dojo/a-deep-dive-into-kentico-12-mvc-widgets-with-vue-js-915612295be3