Here a list of similar tools but may not cover all the watcher features:
I never tried any of this one and not sure that it will work with your elastic version and may work with any future version:
I think the most advanced but last commit is from end of September, with ~100 pull requests <--- maybe lead dev are less active, but have lot of users
I couldn't found back but there's a fork with a kibana interface and may not sure that it work with your version.
This one is very young and have small or nearly no community, if you need support it may be hard...
There a comparison here with more details and comments:
Or if you have small needs you can check here:
Depends on your needs and skill you can choose any of the listed solution or as @rashmi said check the cloud solution.