The Fussy Librarian is one of my favorite book recommendation services. I can choose not only which genres I prefer to read, but the explicitness level as well:
Only The Fussy Librarian remembers what genres you like and your preferences about language, violence and sexual content. Like only cozy mysteries? We’ll only send you an email when there’s a mystery that doesn’t have sex, violence or profanity. Read everything? We’ll send you lots of suggestions each day. It’s that easy!
Have a look at The Musubi Murder and other PG-rated cozy mysteries here.