I want a similar toolkit that lifts over the Ruby/Groovy/Kotlin style functions like countBy, groupBy, sortBy, collate, etc etc. Programming in Python is such a chore without these higher level collections APIs and for some reason (I guess, list comprehensions being considered idiomatic, bare bones itertools being considered "good enough", and the lack of real inline closures?) it doesn't seem like they'll ever be part of Python proper. But I still want them.
Maybe the toolz[0] family would cover your use cases? There is also a Cython implementation if you need better performance.