We have OrdList which does:

Provide trees (of instructions), so that lists of instructions
can be appended in linear time.

And Bag which claims to be:

an unordered collection with duplicates

However the actual implementation of Bag is also a tree if things.
Given that we have snocBag, consBag that implies to me it's
also an ordered collection.

I wondered if besides of someone having to do it if there is a reason why these couldn't be combined
into a single data structure? Their implementation seems similar enough as far as I can tell.