A while ago when I started using Ubuntu and wanted to see other Linux OS alternatives I found this massive and very well organized timeline of multiple Linux OSes.
(Version 21.10)
When I found it I stared at it for a long time trying to read all the names to see how much of them I knew about. It is impressive how much bifurcations there are and it is very exiting to see that the list continues to grow with discontinued or newer OSes.
You can click on the name of the OS and it will send you to a page containing information about it (it doesn't seems to work right now, at least for me). It is a very good image.
The authors of the image are here --> https://github.com/FabioLolix/LinuxTimeline
Cheers and enjoy the image.