Not sure if OP still responds but I’ve searched for some good rings:
- Mythical Belgothian’s Sigil
- Mythical Eternal Band
- Mythical Signet of the Runefather
- Mythical Band of the Eternal Haunt
Also if you have the game on Steam, I recommend updating it to 1.1.9.2 beta Public Testing FAQ because
"Celestial Presence: now reduces % Elemental Resist instead of % Fire Resist. The Transmuter’s functionality remains"
You’ll need to put more points into Celestial Presence then