[Tanasinn]

Endless Quiver is not underpowered. Underused, yes, but only because the number of archers that actually use arrow types is lacking. Tripling the duration and uses of a buff is incredibly potent. I say this as someone who never unequips my quiver on my rangers.

Snake-Tooth necklace is not really underpowered, so much as equally niche. 36% poison resist is a lot to throw out, and you're still getting +2hp/turn and +2 cel, on top of +12 acid attack. That puts it at very competitive(If not inherently superior) to most stat accessories, only 'held back' by being a 10* at all. For a comparison, I would like to point out the Blood Whistle. It's an accessory made by combining other accessories with a craft skill check, and grants 2hp/round, 1 cel, and 2 power to sylphid spells.