かろう => May be... N2
Speculation
だろうか  => I wonder... N4
Speculation
~であろうとなかろうと => whoever; whatever; however; even ~ N1
Innocent
~ かろうじて => Just enough for N1
Description
... だろうが、... だろうが => Whether it's ... or ... N3
Demonstrate by example
どんなに…だろう(か) => how…!; what…! N3
Emphasis on degree
ではなかろうか => is it not so? may be... N2
Argument (indirect assertion)
よかろう => it's okay to have, it's fine even ... N3
Change the subject of the story
たろう => probably is ~ N3
Speculation
…だろうに => surely… N2
Speculation
だろう => Probably A N4
Sentence Endings
ことだろう => Perhaps... N3
Speculation