fandom progressions

Tortall, Ragwitch -> Young Wizards, Kiesha'ra series -> Outlander series, Private Series, Shopaholic -> apathy -> Temeraire, Collegia Magica, Kushiel's Legacy -> ??

I still revisit some of them once in a blue moon. MLP:FiM, IPS, and others don't count, because I never wrote fic or went looking for fic, just enjoyed them (and that can be said of literally hundreds of books).

So!
Yours?