Order Him a Single Malt
You're supposed to meet at the bar. He's running late and feeling stressed. Your phone lights up a text: "Will be there in 5, sorry!" Order him a good drink, on you. If he's a scotch man, get him a single malt. If he's more into beer, select a unique IPA. It's super sweet that you know his drink order. And if you can take it up one notch price-wise to something he would not normally order for himself, but is in that same wheelhouse, he'll be charmed for sure.
Bring Home Dessert
You've been out the girls all night but are crashing at his place, or perhaps you live together. On the way home stop by that Italian bakery he loves and grab a cannoli. He may not necessarily be hungry but he will love that you thought of him. And it's a cannolijwho can't rouse themselves to be hungry for a cannoli?
Get that Broken Thing Fixed
It could be that watch that needs a new battery or the defunct zipper on his favorite messenger bag, but when you spot that broken item sitting in his apartment scoop it up. These are often low cost fixes. It's the sort of thing that is just inconvenient enough that a guy won't do for months since it's not a priority, but will be so thankful that someone else did it for him. He'll always think of you when using it thereafter.
Traditionally men buy flowers for women, but why can't that gesture go both ways? Men like having their apartment lit up with beautiful sights and smells too.
He just checked into the hotel for a trip away. He already misses you. He opens his luggage and on top of his clothes is a handwritten note from you saying just how much you love him. His heart will melt and he will keep it in his bag for years to come. Any sort of homemade card, for anniversaries, birthdays, or just because is a very sweet gesture. Don't be surprised if he squirrels your card away; most men have a designated place for such treasured items.
Framing Writing He Loves
He loves that one song way too much, or he sent you a poem early on in your relationship. Whatever that meaningful collection of words may be, transform it into a simple piece of art. You can calligraph it yourself, or have it printed in a strong font on good paper. Slap a simple black frame on it and it's a personalized piece of art that he will love.
Surprise him with a date night, but don't tell him in advance what you're going to do. Base the date on one of his passions or interests. If he loves a good whiskey, take him to a whiskey tasting. If he is into cars, take him to a car show. You show that you care about his interests and are willing to explore them with him, which says a lot about how you feel about him. Don't be surprised if he reciprocates with a similar date based on your interests in the future.