red olive 901I know it answers the questions how, when, where, in what way, to what extent but are there others?
I don't think so.
I don't look at adverbs that way myself. I try to see what role a phrase plays in a sentence by asking myself what it modifies. It is not always easy to tell, but if it is a verb-like thing, an adjective-like thing or another adverb, I call it an adverb.
red olive 901Can somebody enumerate all questions that an adverb can answer, especially if it modifies a verb?
I doubt it, and even if that were possible, it would not necessarily help you to classify an adverb when you see it in a sentence.
Most adverbs that modify verbs focus on place, time, frequency, or manner, but I suppose you already know that (here, now, often, slowly).