A question that might be good to answer there is if the gear stacks with each other IE a Serpents Coil + Abyss STR check RING would it be +4, +6, or +10? I think the answer is +6 but I am not really sure myself.
As far as I know: Only ONE bonus from item stacks with the corresponding paragon feature and thats it. Let's say: Anchoring II from asmo belt (+4) and paragon anchoring (+4) gives +8 to STR checks. Equipping an Indormitable Bracer from Ely (which has anchoring I, another +2)) doesn't increase the saving roll any further.
In the BUR item category I have made a list: wiki.hgweb.org/wiki/Category:Beyond_Ultra-Rares One feature is that you can click on the "Inventory Slot" column to sort the items by their type. In the Remark column is a quick overview what the item is (needs some more polishing, tho)