I switched up my manly tractor birthday card (https://www.etsy.com/listing/104686399/manly-or-for-men-birthday-card) to make it a manly Valentine's Day card.
I call it a Man-lentine!
The card is a sheet of real wood and has a green tractor affixed to it. The tractor is carrying a pile of hearts and the inside reads: "Piles of Love."
This Man-lentine is also available in my shop for $3!
This one isn't SO manly, but I think the cork background makes it less frilly/girly.
It is a stamp that says you hold the key to my heart, there's a plastic key attached, and it has a cork background.
The latest installment in my Man-lentine quest is this card which features a lawn mower. The inside reads, "I love you mower and mower." The card has a burlap background with green grass, a red mower, and a little blue cloud.
This card is not really geared for men. It is a rose embossed cover with a black bird cage die over a small red heart. The inside reads, "you have captured my heart."