We do not yet know which TCG expansion that these items will be available in and whether or not the Feldrake is the equivalent to the Timewalkers Mount that is labelled [DNT] in the screenshot above. Hopefully, it will all be revealed to us soon. The Timewalkers Mount sounds to me like it might be more akin to the new chromatic dragon mount models found in the previous patch. At this point, we do not have concrete details.
Brace yourselves for what could be some of most exciting updates to the game recently with patch 4.3. Review the official patch notes, and then dig into what's ahead: new item storage options, cross-realm raiding, cosmetic armor skinning and your chance to battle the mighty Deathwing -- from astride his back!