The 18 family-related words found in the word search puzzle are:
1. Granddaughter
2. Daughter
3. Mother
4. Father
5. Brother
6. Sister
7. Cousin
8. Uncle
9. Aunt
10. Grandmother
11. Grandfather
12. Son
13. Grandson
14. Nephew
15. Niece
16. Parents
17. Family
18. Relatives