Two Radeon Vega logos have been unearthed on the trademarks section of the Justia website. Surprisingly, there is no red present in the two trademark images: One of them is colored blue and the other is monochrome. It's not known what product AMD might be planning on using the images with, if any.
https://www.notebookcheck.net/New-AMD-Radeon-Vega-logos-spotted-in-legal-trademark-database.419769.0.html