This perfectly summarizes the situation:

This is how I feel as I’ve been researching Arthurian family trees and the relationships between characters.  There are so many interconnecting relationships and different interpretations that I have been unable to find one that I feel encompasses everything.  Besides maybe this one above that I can’t even read.  So I have decided just to collect the ones I find that are the most coherent and common, and at the end of my study I will make my own, incorporating everything I have learned.  Here are the most helpful I have found so far:

These first two are from Nancy McKenzie’s Arthurian novels and are my favorite so far.  The first one concerns Arthur’s line, while the second relates to Guinevere’s line.

These three are from the Timeless Myths website, which has many other interpretations of the Arthurian genealogy and shows the evolution of the different relationships.  The ones I used are the most recent and were developed after the Vulgate Arthurian cycle was written in the 13th century.  The first one is the line of King Arthur, the second is the line of Lancelot and other knights, and the last is the line of Cornwall, which relates to the stories of Tristan and Isolde.

This last one you will definitely need to click on to read.  It is about as complicated as the very first image, but a bit more organized.  This will be a good one for me to refer to when I come across new characters and relationships.

There are obviously some discrepancies between these genealogies, but I feel like they give a fairly comprehensive view of King Arthur’s family tree.