They are all over Central Park. Plaques with names of loved ones who passed away, who used to sit on these benches, those who used to pass by underneath these trees. One could imagine ghosts coming back to these places late at night, when the park is that scary place where living humans should not sit around.
Not all of these metal plates deal with loss and with loved ones who passed on to the other kind of Central Park.
My favorite inscription in the Park does not even celebrate a human being. In a really good spot, right behind the Metropolitan Museum of Art, right near Cleopatra's Needle... one can find the following plaque:

In celebration of the extraordinary life of
Lord Randall the Bulldog
and all other canine companions
who pass this way