The mentions of Silverlock (I'm proud to say I own a 1979 copy) made me think of another book in which many famous people appear -- The Fabulous Riverboat and To Your Scattered Bodies Go by the strangely brilliant Philip Jose Farmer. I'm not reading any of that at this time, so I'm sort of cheating here, but the books deserve attention, especially as an entirely different sort of fantasy.
Mystagogue
Istari
Apprentice
Shadow Lord