Every book I read refers me to many other books, there is practically no way I can read all this text in my life time. Once and for all, where is the best place to fish for ideas?
There are lots of different sources out there where you can find various quantitative strategies.
Usually, different blog aggregators like https://www.r-bloggers.com post on their websites interesting new approaches and techniques.
You can also find great deal of information on Quantopian's dedicated page here: https://www.quantopian.com/posts/trading-strategy-ideas-thread
ssrn.com and arxiv.org also may be useful.