Maybe a pen or keep sake with a personal message engraved on it. If you’re in the US check out the store called, Things Remembered. Personalized Gifts for Him at Things Remembered
Is he into technology (playstation, cell phones, computers)? A gift card to Best Buy or any other favorite store of his is an option.
Treat him to a nice meal at his favorite restaurant
Go for small romantic getaway/vacation to his favorite place
Cook him his favorite meals for breakfast/lunch/dinner/dessert