Gandalf
"Gandalf The Gray", he was known most of his life.
Known to some that is.
Mithrandir he was to the elves and even They didn't know all there was
to know about him.
He was both the doer of small things,
(like aiding the company of Thorin
Oakenshield and their hobbit burglar,
Bilbo, in their quest for the treasure guarded by fierce Smaug.), and of
great (fighting the Balrog, moving a lot of the important things in the
War Of The Ring...). And these examples only extend to the last 50 years
or so of his activity.
Gandalf, too, is a Sage Wizard. He accompanies the heroes, gives them
advice, sometimes tells them what to do, but mostly he remains in the
background doing "his" stuff (which of course turns out to be connected
to everything and helpful).