Find players again on Xbox?

Today I met a really cool person while gambling, but then my connection was interrupted. Since we have not joined as friends yet, I can't find him anymore. He will also not appear under "Last Player". I still have his Gamertag in my head, but I do not remember the numbers at the end.

Is there a list or similar where I could enter the Gamertag and then all profiles that have a similar Gamertag appear? Or can I find him again somehow?

Although I have no Xbox but as far as I know must be in the Friends list or somewhere else "Player encounters".

Yes, that's just this "Last Player" section: /

Then you can't find him again, I'm sorry.

Oh, okay, really bad.