Hi, Cortland --
It sounds like what you're looking for is the Surname Index page. For example, https://www.wikitree.com/indexes/person/A/index.html brings up all the A names along with a menu to jump to a specific letter.
You can also get there using this URL: http://www.wikitree.com/genealogy
I understand that the One Name Studies participants like to use this index to easily find name variations to work on.
No. That is not it. That shows your personal surnames. It used to be under the "find" tab below under "Social Media". You could click on it all Surnames would come and you would type in the name you were looking for. Then type in the first name and it eliminated a lot of profiles. It made searching so much easier. Now it is gone.