There’s Peerages. Burke’s and a less formal one. Burke’s only lists those in line to a specific title (or Peerage). There’s only so many Peers. The less formal one also shows members of families who had connections to the royal family otherwise. Like military, ladies in waiting, etc. First anon was correct. Second one was mistaken. I actually think the less formal one is even a hobby for some guy. Wanna see something hilarious? YouTube “Tim Nice But Dim Interview.”