The Amrath storyline contains a series of quests leading up to the Tower of Despair raid, as end rewards here you'll find rings which have an attribute called "Incredible Potential".
Completing the raid also grants you Shavarath Trophies of War. By collecting 9 of these trophies and adding an Imbued Shard of Great Power you can add various attributes to your rings. Also, these rings make up set bonuses with other named items found in the area.
Access to Amrath, completion of Tower of Despair raid and its pre-quests are required.
From the DDO Wiki