Having Sil e Rahm is wajib with which relatives other than parents and siblings? Also, on in laws side who are included with whom it is wajib to stay in contact with?

Rahem are blood relatives, so that includes grandparents, uncles, aunts, cousins, etc… It is mandatory to not cut ties with them and be on good terms.

As for the in-laws, they are not rahem, but morally we are to treat them well, have good ties with them and show them kindness.