It would be nice if you could tell at a glance how many of these are forks, versus just installing unmodified upstream Kubernetes.
https://landscape.cncf.io/category=certified-kubernetes-dist...
We've split Certified Kubernetes offerings into 53 distributions (meaning they make changes to upstream and/or add software), 35 hosted platforms (meaning they manage K8s for you), and 19 installers (meaning they just install vanilla K8s).
Disclosure: I manage the Certified Kubernetes program and the Interactive Landscape shown above.