There are enough Linux distros that have not been reviewed or made it into the top 100 of the Distrowatch main page to keep you busy for months, even if you try one a day.
And that is just Linux distro’s. There are sub sections of distro links that are not based on any distro, or even Linux, but stand alone.
The Distrowatch related link page is: http://distrowatch.com/dwres.php?resource=links
I do not have any relationship with Distrowatch, but as a reformed distro hopper, this Distrowatch links page reads pure gold if you are a hard core distro hopper!
Caution advised, some of these distributions are not for the feint of heart, and from what I read, some are not so friendly either.