Oops, it doesn't look like 'sibling or pet day' is a national day..

Other days

Nail Polish Day

Hannah Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Frozen Yogurt Day

Cursing Day

Appreciate Yaself A Lil Extra Day

Tell Ur Crush You Like Them Day

Lash Day

Stress Awareness Day

Mean Girls Day