LogFAQs > #973880176

Barbara is the F2P healer, she's not very good but can be made to work if you're desperate. Especially because Hydro is kinda just a busted element.

The catgirl is a shielder, which is basically as good as a healer since you don't typically need two defensive units. I don't know much about her but I heard she's very solid for a 4*, and Dendro is also very powerful so she'll pair well with Yae Miko.

There's other types of supports but they're not as obvious and depend on your team setup (Yun Jin qualifies), so you don't have to worry about it too much for now, but if you start lagging behind on resources it's safe to just focus on a couple of damage dealers.