select * from U&"\2764";

using \dt U&"\2764" throws an error
but \dt ❤ produces the correct result:

cms3=> \dt ❤
       List of relations
 Schema | Name | Type  | Owner
--------+------+-------+-------
 public |  ❤  | table | cms3
(1 row)

Except, I had to copy the emoji from an emoji page to get it to try to show as a red-heart in this page.
Using the html entity code, I only get a black heart.  🖤 Weird.
Note the actual black-heart html entity code produces a slightly different heart.

Editing it breaks it, changing what it decodes back to from the database.
Must remember to insert 🖤 entity codes to get the shiny black-heart
And ❤ entity codes for the red heart. ❤️