I loveeee when the MC or ML has to take care of a child that is a younger sibling/cousin/nephew or niece. Especially when they are already struggling and there's at least somewhat absent parents. 

I love it be the MC, ML and the child become like a little family it's so cute.
A lot of these will be school life but I'll try to add others.

It's also very hard to find bc they sometimes aren't put under the younger brothers/sisters tags and they are also not under the childcare tag so I'll try my best. Let me know if you know of any!