Nah, I mean practical libraries that would actually help our codebase..

In my stack (Android) : started adopting EventBus while Rx was already pretty mature, deep into spaghetti code architecture while it has already been showed that variations around MVP or MVVM would be very beneficial.

I can't go into too much detail here but when there are some very big challenges around this product which faces an enormous memory usage and tons of memory leaks.

I am very practical and don't feel the need to use all the latest toys but here these are cases where the product could have been greatly improved by being a part of the community instead of living in an ivory tower where you are absolutely distrustful of external code to a ridiculous degree.