Obviously, the best raiding Ret Libram is the sexy, wonderful and fantastic Libram of Valiance. Everyone loves an effective 200 passive Strength from the Relic slot but it comes at a price: 25 Emblems of Triumph.
For those not yet well advanced in TotC-10/25 and regularly smacking up Koralon EoT's are hard to come by and worth their weight in gold. If you're not DPS as your main spec you should rightly baulk at the price, at least until there is no more main-spec gear for you to buy. So, what Libram should you go for?
Well, the best choice was previously the Libram of Radiance, but 25 EoV's = 25 EoC's and so it comes at a very high cost. Don't rely on getting lucky with this as a drop, the drop rate is atrocious. And anyway, there is a better option.
Season 7 just started, and there's been a new development: PvP Relics's are now available for Honour! I've mentioned before that the PvP Libram's are great for PvE but previously they've required an Arena Rating and Arena Points to gain. In a PvP Season transition the old second highest tier (now 3rd highest) is usually made available with Honour, but that hasn't included Weapons (much to my chagrin) or Relics. The same is true this year, with one exception: Deadly Relics can now be bought with Honour Points and no Rating requirement!
WoWHead is still (wrongly) listing these items as requiring an Arena Rating of 700 and some Arena Points. However, all Deadly Relics can be bought from Zom Bocom, the Apprentice Arena Vendor in the Dalaran Underbelly, for the low-low price of 15300 Honour Points. Okay, it's still something of a grind, but well worth it for Relic using DPS Off-specs and maybe a few Healer specs too (the DG Holy Libram for example gives 334 additional Spellpower to your FoL for example).
The Deadly Gladiator's Libram of Fortitude is worth 120 Passive AP. It's not a patch on the Libram of Valiance, but definitely the next best for players with no access to the Arena.
Thanks go to new WoW-Blogger Ayrlyn and her blog 'The Light, and How The Swing It'.