keeping in mind I haven't done Chiori or Emilie's yet (though I don't expect them to rise to the top lol):

Neuvillette, Tighnari, Dehya, and Nahida's 2nd one

after those 4, I also really love Yoimiya's 2nd one, Furina, Xianyun, Hu Tao, Itto, and Baizhu. (straight up went into Baizhu's thinking "ok let's get this over with" and was really pleasantly surprised at how interesting it was)