In my opinion, the only true "unique" relic was Eureka. There was no way to earn it outside of running that content. Sure, Bozja had a few steps "locked in" but most of it was optional and could be earned elsewhere:

- ARR: run dungeons, FATEs, grind tomestones for various tokens (Alexandrite maps, oils, atma books, etc), run old content for light farm.
- HW: run dungeons, FATEs, grind tomestones for various tokens (aether oil, umbrite, ink, clusters, beast tribe items), run more old content dungeons/trials
- SB: Eureka only
- ShB: Grind tomestones from running old content, earn tokens in Bozja or from FATEs, run leveling roulette, run ARR/HW/SB 24-man raids for tokens and HoH for tokens

Other than SB, all of the other ones focus around running old content... so how is grinding tomestones for the EW relic really any different than these previous relics? Instead of grinding 1500 of them, do you want to buy 5 100 tomestone items, 2 250 tomestone items and 1 500 tomestone item and turn them into various NPCs to progress the quest?


Same with HW and ARR relics. Much of those were all about obtaining certain items by either spending poetics or beast tribe quests, etc. ARR mixed in FATEs, Levequests, etc. It was sort of a "capstone" questline.
However, SB relics remain the only relic that has the entire content all wrapped up in those four Eureka zones.