Genshin Impact Barbara's Party Healing Showcase
Barbara's "Let the Show Begin" party healing heals other party members with each hit which scales with her HP. As you can see, I have 16k HP on her and each attack hit heal all my party 250~ HP and 1k~ HP for the charge attack.
For the character HP themselves:
Noelle 17,517 HP
Barbara 16,633 HP
Xiangling 9,586 HP
Amber 6,923 HP