Darkmoon Deck: Promises – The top mana regen trinket right now.
Amalgam’s Seventh Spine – A very good mana regen trinket that synergizes with PW:S.
Ephemeral Paradox – Drops in NH, free Atonement applicator and a heal, along with mana return, however the proc rate makes it mediocre at best.
Fluctuating Energy – Decent if empowered with chest. Not a recommended choice.
If you’re curious how all trinkets compare to each other, please refer to this spreadsheet.
If you’re curious on how mana trinkets compare to each other, please refer to this spreadsheet.