Something really interesting I've seen both on some streams and in my own games is that Control Warlock decks (the kind with Oakheart and the new Spellstone and of course Voidlords) are actually running Rin. They're just so heavy control with so many defensive cards that they can afford to use her despite how slow she is, and it can really actually put a timer on you since you're more than likely not going to be able to kill them before they destroy your deck with Azari especially with how good their healing is now. Plus, N'Zoth is there sometimes too to revive stuff like Rin and the Voidlords so even Dead Man's Hand Warriors aren't necessarily safe from deck destruction. I don't know if she'll remain in these decks once things get refined more but it's cool to see her being played at all.
It's a shame it's still countered by Jade Druid, though, cuz Jades remain the most degenerate mechanic in Hearthstone. I weep for Wild because it'll always exist there.
EDIT: Something fun I've also been seeing is Spiritsinger Umbra combined with Carnivorous Cube onto a Doomguard, so it eats the Doomguard and instantly summons the two copies because of Umbra which an attack with charge, then when it dies you still get 2 more Doomguards.