You could use the word relatives. If I were talking about having extended family over to my home I'd say, "My relatives are coming over for a visit."

Hi, I'm a native English speaker and I can't think of another way to refer to people outside of the nuclear family besides "extended family". 

I agree with "relatives", and would add that we can talk about one side of our family or the other: "my dad's [side of the] family" or "my mom's [side of the] family" for the respective sets of people.

<em>We had vacations with my mom's side of the family when I was a kid. </em>