Surprise surprise, Cloudstone Curio is a busted with yet another card. Keep bouncing 1 or 2 mana changelings to your hand and trigger your infinite lifegain off Tolsimir, vindicates from Reaper King, card draw off Unesh or Wirewood Savage, etc. Gilt-Leaf Archdruid draws infinite cards as well, and then once you have 7 changelings in hand you can play them all, then with the Curio trigger on the stack, steal someone's lands, resolve Curio to bounce back a changeling, then play it again to return your tapped changelings to hand then replay them again, effectively untapping them to steal the table's lands. Aluren offers a bit of redundancy to this combo as well (though TBH with three direct-to-play tutors, it's probably egregious). Curio is also a good card by itself, since the deck has so many cheap 1-2 mana changelings (with more hopefully coming with MH) so it can juggle them to trigger Lathliss and Spit Flame and the like. With the tutor creatures you can also save your important creatures from wraths with Curio.
For a more tribal-based combo, Hibernation Sliver + Tolsimir, Friend to Wolves gets you infinite life and infinite ETBs with any cheap changeling. If you have a haste outlet and a mana-maker, it's also infinite mana. Hibernation Sliver also seems decent in the deck already for the same reasons Cloudstone Curio would be. There's also probably something you can do with Arcane Adaptation to break it, but right now I'm not seeing it.