The Sombra Demon Hunter BlizzCon skin was not exclusive to BlizzCon 2018 Virtual Ticket holders. See this post for more details:
http://www.mystgraphics.com/OverwatchForumImages/blizzconitemnonexclusive.jpg
Please note, this year’s skins Tyrande Symmetra and Illidan Genji, appear to be exclusive to the BlizzCon 2019 Virtual Ticket.