Is there a lounge for minors flying alone?

Usually you should inform the airline if a minor flying alone. They will usually accomadate by assigning someone from the team who watches your child. E.g. walk them to the back and make them sit upfront on the flight and other goodies. Ive done it alot as a kid. There may be some additional fee depending on the airline.

Couldnt find one.

Absolutely We have special lounges for who fly alone !!! Please come over and enjoy !!!

Not that I know of unless you have a membership to places like The United Club