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

Other days

ruby

Ruby Day
prosecco

Prosecco Day
kale

Kale Day
tulip

Tulip Day
lumpy rug

Lumpy Rug Day
self appreciation

Self Appreciation Day
bounce

Bounce Day
gum

Gum Day
singles

Singles Day
gallery

Gallery Day