Anne Bishop's Black Jewels Trilogy.
As a young writer I was always told I couldn't do specific things like change point of view or use third person omnipotent with multiple characters.
As I got older I was told I shouldn't write Urban Fantasy because it's all just like Twilight and junk. It wasn't "real" fantasy.
Every time I start to second guess myself, I reread this trilogy (and all the rest of the series... and all the rest of her books in general). I see that my style IS doable and that there is more to Urban Fantasy that sparkling vampires.