I think it was in reference to it being a highly opinionated list. Especially since I've been developing for Android since 2010, and most of the actual "best libraries" were absent from this list.
Also, I've never heard of CloudRails (though they do seem interesting for certain use cases), but I'd never put them on a par with Retrofit, and leave out some of the more established names.
Exactly this. I've never heard of CloudRails, from my own development experience, on conferences or meetups or posts. Retrofit (1&2, Volley, those are the libraries that deserve mention there. "Database" category having just two libraries is like someone didn't want to bother, since Android has a lot of ORM libraries and also databases like Realm.
Date & Time doesn't even have Joda-Time for android, DI links to Dagger which is deprecated in favour of Dagger 2, Functional includes only Retrolabmda, no even mention of RxJava and all the libraries surrounding it, Camera is missing some most popular camera libraries, Logging doesn't include the most used one - Timber, Image doesn't include Picasso or UIL... I don't feel like scrolling anymore, there is a lot missing, especially since the list is called "Best Android Libraries".
Also, I've never heard of CloudRails (though they do seem interesting for certain use cases), but I'd never put them on a par with Retrofit, and leave out some of the more established names.