There is no one site where publicly available books are classified like this. Lots of people do their own testing and come up with different results, but the reality is that once any book is publicly available then it will quickly become weak. People will play games against that book and will then analyse the games and tune their books to find stronger lines, so what are strong lines one day may be weaker lines 3 days later as people tune their own books to find even better lines. Also there is no such thing as "strongest" book -it depends on your hardware, engine, hash size, tablebases etc etc.
The strongest books are those that are private and which people have hand tuned themselves. If you want a strong book then take any of the leading books available for download (some are available in this forum) and you then need to spend a lot of time hand tuning them. This can take a lot of time as you need to tune the book after you play some games and then keep on doing this again and again. Here is one simple way to hand tune a book that I have found very successful although it takes some time and effort. Use the book to play some engine games. Then play back over the games until you reach the point where either the book line ends and there are no more book moves, or the point at which you begin to get negative evaluations. Then set your engine on infinite analysis for a while so it goes quite deep in it's search and by doing this you will find the best next move - then add this move to the book line to extend it. Then next time your engine plays the same line it will make this better stronger move!
To manually edit the book go into Fritz and do File/Open/Openings Book and select the book you want to edit. Then select the Openings Book tab on right hand side of screen. Basically you can either:
Add a new move to the book, To do this right click somewhere in that book area (not on a move just in empty space) and tick Allow Move Adding. then when you play back through a game and want to add new line, just make the move on the actual board and then select new main line from the options. This will then have added the move to the book. You can do this for as many moves as you like so you can extend a book line quite significantly.
Change the 'weighting' of an existing move making it more/less likely to be chosen. This is shown in the Prob / % column. To change it right click on the actual move itself and do change weight. The value is from -125 (very unlikely to be picked) to +125 (very likely to be picked). You can change these manually to any value. Actually this is what the automatic book learning does based on whether games are won or lost - but this is how you do it manually.
Mark moves either red (means they won't be played ever) or green (mean they will be picked, with a probablility given by the % column). To make a move red right click on it and select Don't play in tournament
To make a move green right click on it and select Main Move. You might want to make a move red if you find that at some point in the book line you had a negative evaluation and therefore you can mark that move red so it won't be played again.
There is a lot more to it than this but this should give you enough to start editing your book to tune it to make is stronger. I hope this helps you.