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

Other days

one

One Day
slime

Slime Day
bonang

Bonang Day
kiss a brunette

Kiss A Brunette Day
artists

Artists Day
cat girl

Cat Girl Day
carpenters

Carpenters Day
hoodie

Hoodie Day
kiss a ginger

Kiss A Ginger Day
pampering

Pampering Day