The ones written on a cafe napkin. All crumbled and creased. Just a fountain pen that she carried. And a white napkin that she leased. (Had to make it rhyme :P)
'Hindwi' is an ig page on hindi poetry, which has posted some excerpts of love letters of great hindi poets. Check it out. It's a sub page of 'Rekhta'.
An excerpt from Comedian David Mitchell's memoirs about meeting and marrying his wife. Not a love letter addressed to her but definitely a love letter to her. The excerpt from the audiobook is also out on RU-vid