I would recommend Mushishi to anybody from age 5 to 105. I just finished rewatching it with my mom.
It’s kinda like Pokemon but instead of animals the “Pokemon” are usually fungi or diseases or natural phenomena. The series takes place from the point of view of a traveling doctor / scientist who uses his knowledge to help people.

While I do think it’s appropriate for any age group and I think I would have liked it as a kid, it might be scary or boring for a little kid.

The first episode is pretty uncharacteristic of the rest of the series, so if you check it out I’d recommend judging it based on episode 2.