I'm going to ignore your request for coming of age stories. You have apparently read all of the ones if have. So here are some authors that i love and you might not have heard of. I hope.
Have you read Simon R Green I recommend anything he's written. Steven Brust is another fantasy author that I like but doesn't seem to be that well known.
Glen Cook is another talented but underrated author.
John Scalzi is my favorite modern sci fi author. I'd suggest Agent to the Stars.
Larry Correia writes modern fantasy (present day or the 1920's). He is a very good author if you are looking for something entertaining.
Oh and please tell me you've read Heinlein. If you have, awesome. If you haven't, punch yourself then go buy everything he ever wrote.
Ken Scholes writes "The Psalms of Isaak". Now this is a high fantasy epic that does have a child protagonist. Very good series so far.
That's all for now. I could think of more but it's late. Will add to the list later if you'd like.
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