Grandiose items are randomly given Missions in your Garrison.
Do not worry about them if you are level 100. On Tuesday, the intro to unlock Tanaan quest line gives you four 650 item tokens (Baleful Treads, Baleful Tunic, Baleful Gauntlets, Baleful Girdle) and at the end, a different token that will upgrade a 650 Baleful token to 695.
The 650 base item tokens drop randomly throughout Tanaan from rares and can be found from some treasures. You can also
buythem for Apexis. 5k for a 650 Armor/Trinket/Ring/Neck Token. 10k for a 650 Weapon Token. You can then buy the
Upgradeitem for 20,000 Apexis each. It will upgrade a TOKEN to 695.
Sort of like the Burdens of Eternity and the Timeless Isle tokens. Do not use a token if you intend to upgrade it. You must upgrade it first.