You can purchase Armor/Weapon Ensembles of War Mode Gear from previous Dragonflight PvP Seasons with Bloody Tokens in Patch 10.2.
The weapon arsenals and armor ensembles can be purchased by Warkeeper Gresh in Valdrakken.
Bloody Tokens drop from many PvP activities in the Dragon Isles when you turn on War Mode.
Thanks to MrGM for the screenshot.