Why don't you vendor them?
My chests are just full of trial sets i think i might use in the future.
Honestly I just like hoarding them, plus I like the idea of having a treasure chest where I keep all of the stuff I get that's worth something from trials.
I've recently started to collect the trophies from trials, Undaunted Plunders and the such, wondering what other people hold in their chests of goodies, post them below.