Oops, it doesn't look like 'xd day' is a national day..

Other days

slime

Slime Day
boba

Boba Day
ruby

Ruby Day
ponytail

Ponytail Day
eat what you want

Eat What You Want Day
fiancee

Fiancee Day
unicorn

Unicorn Day
first love

First Love Day
special education

Special Education Day
kiss a brunette

Kiss A Brunette Day