Books in Series
DeeAnn Merhoff

Children/Juvenile Fiction Books in Series

Intermediate and YA Books

Adult Fiction Series

Extensive General Readers' Advisory

Fantastic Fiction

SciFan: Science Fiction and Fantasy Series, Prequels and Sequels

Juvenile Series and Sequels

It's a little pricey, but I use The Whole Story: 3000 years of sequels and sequences. I think the latest is the 2nd edition, ISBN 1864520221. It's got about any series listed by individual title, author and name of series.

I have a book called "Fiction Sequels for Readers 10 to 16: An Annotated Bibliography of Books in Succession" that I use
religiously. It is 4 years old now and I try to keep it up-to-date.