The Gate of All Realms
A navigation website has many links to websites, and each link can open a web page of a website. And every website is equivalent to a world, and every link is equivalent to the door into that world. And your navigation website is a collection of doors that can reach all websites that have links. Therefore, it can be called the "Gate to All Realms". There is also a fantasy flavor, and it can also show that your navigation website has many website links.