One solution:

    # return map(compose(list, second), itertools.groupby(seq, key=f)) 
    return (list(v) for k, v in groupby(seq, key=f))

The recipes.py solution would be for those function that needed to use both functionality from itertoolz and functoolz.  If both compose and second are required then this function would go in `toolz/recipes.py` rather than `toolz/itertoolz/recipes.py`. 

I'm not sure I've answered the "what did you have in mind" question; let me know if I should give more clarification.