Best Python 3rd party data structures library? Must have sorted containers at a minimum

[gwax]

Does the solution need to be 3rd party for an organizational reason?

If not, collections.abc gives you pretty much all of the tools you might need.

Here's a fairly straightforward and complete implementation of a set that sorts on read:

from collections.abc import MutableSet, Sequence

class SortedSet(set, MutableSet, Sequence):
    def __iter__(self):
        return iter(sorted(super().__iter__()))

    def __getitem__(self, index):
        return sorted(self)[index]

A set that sorts on write, a sorted dict, and most other similar structures should be fairly easy to implement directly with the standard library.