Added along with Hibernation Crystal from Ysondre, for those that have the Dragons available to them.
Sheet doesn't consider set bonuses but I'd imagine t2 3pc is relevant all game for fights that require a lot of chain healing. The t3 set bonuses don't look anything too special to seek out, 2pc saves some mana but it's not very much, 4pc would be useful and you'll probably be using 4 pieces anyways, 6pc is intriguing, and 8pc looks like you'd probably be giving up too much mp5 from offset pieces to really be worth it.