There are a lot of Linux distributions. I can’t even think of coming up with an exact number because you would find loads of Linux distros that differ from one another in one way or the other.
Some of them just turn out to be a clone of one another while some of them tend to be unique. So, it’s kind of a mess – but that is the beauty of Linux.
The list at https://itsfoss.com/best-linux-distributions/ lists some of the best in each category.
#^https://itsfoss.com/best-linux-distributions/ lists some of the best in each category