I'd say all relics are a 10, usefull or not, due to the price tag alone.
Well, except for Claustrum. That one is less useful then N.Q elemental staves.
Wave Four:
Aegis (10)
Bandomusha Kote (6) They're useful. Albeit not all that
Crimson Scale Mail (3) They serve one purpose only, to complete the set. -breath damage can be usefull, albeit rarely. It also looks better then Errant, so that earns it some extra points.
Gjallarhorn (10)
Maat's Cap (7) This one mainly says "I have all jobs at 65+", its also a mini kirin osode. It is, however, useful to swap in for WS/spells for some jobs, such as BLU. Probably the best one to do so with for BLU.
Peacock Amulet (4) Only the camping sucks. Could however easily be replaced with Peacock Charm.
Shadow Mantle (3) Pretty much useless, since you need low HP for it to activate often...
Shadow Ring (2) See above, but with magic.
Trotter Boots (2) Easy NM to kill, and not that uncommon drop.
Yinyang Robe (6) A very good body piece for SMN. however, not rare, and easy to get, which causes it to lose points.