What are some examples of "unrelated siblings"?

This question isn't about people so much as it is about anything else. It's hard to explain outright, so I'll use an example:

A few months ago I read Emily St. John Mandel's Station Eleven. I just finished with Ling Ma's Severance. The two books are completely unrelated but feel very, very close to one another. There are a lot of topical similarities: both portray a global pandemic, a lead female character, and narrative shifts between pre- and post-societal collapse, etc. However, more than that, both feel very tonally similar. I couldn't read Severance without constantly thinking of and comparing it to Station Eleven, and I think I liked both books better together than I did either of them on their own. Even though they're clearly different and written by different people, they very much feel like they come from the same family -- like they're unrelated siblings.

I'm curious as to what other examples people can come up with, in whatever category you consider: media, historical events, languages, etc. Anything goes as long as they have a familial resemblance.