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A fanlisting is simply an online listing of fans of a subject, such as a TV show, actor, or musician, that is created by an individual and open for fans from around the world to join.

Teddy/Victoire
Teddy is first introduced midway through Deathly Hallows, born to parents Remus Lupin and Nymphadora Tonks. His parents die in the Battle of Hogwarts, killed by Dolohov and Bellatrix respectively. Teddy is raised by his grandmother, Andromeda, but is a constant visitor at the Potter residence.

Victoire is introduced in the epilogue of Deathly Hallows. Little is known about her- she is the first daughter of Bill and Fleur (as stated by Rowling in an interview) and at the time of the epilogue, is in her final year. (Teddy is a year older.)

From the book-
James had reappeared; he had divested himself of his trunk, owl and trolley, and was evidently bursting with news.

'Teddy's back there,' he said breathlessly, pointing back over his shoulder into the billowing clouds of steam. 'Just seen him! And guess what he's doing? Snogging Victoire!'

He gaved up at the adults, evidently disappointed by the lack of reaction.

'Our Teddy! Teddy Lupin! Snogging our Victoire! Our cousin! And I asked Teddy what he was doing-'

'You interrupted them?' said Ginny. 'You are so like Ron-'

'-and he said he'd come to see her off! And then he told me to go away. He's snogging her!' James added, as though worried he had not made himself clear.

'Oh, it would be lovely if they got married!' whispered Lily ecstatically. 'Teddy would really be part of the family then!'

-Nineteen Years Later