Can I search for someone on Facebook just by the first letter of their name?

It is highly unlikely that anything remotely like this would work, unless the first name was incredibly uncommon. As in, only ten - one hundred people in the world.

I ain't kiddin'. Facebook has over 1.1 billion (yes, that's with a b) daily users, and over 1.8 billion monthly users. See: https://zephoria.com/top-15-valuable-facebook-statistics/

This is one of the reasons why search is so difficult there. It is also difficult because FB isn't meant to work like a search engine. Rather, they know that their mission is to keep users on as long as possible, so as to deliver as many ads to them as possible. Therefore, search tends to work toward providing who or what a user is anticipated to want.

You would do better trying a Google search, as Google's mission in life is to provide as good a search experience as possible. And while they do some predictive sorting by location, they are more committed to getting you a good result.

So your search might look something like this:


And that will also take you forever, but it's a shot. Spoiler alert: I really, really doubt you will find someone this way.

Thank you for replying. I knew it was a long shot. Oh well.