A handwritten note to each other would be a super sweet thing to include (either on its own or accompanied by a gift). Other gift ideas could be an engraved wallet, a custom shirt, a bottle opener with a pack of his favorite beer, a gift certificate for a date night (maybe to a nice restaurant, or a movie, or an amusement park, or a touristy activity in your town that you've never done, etc), or something that aligns with his interests. I suggest doing something practical that he can use frequently. Check on Etsy for personalized gifts, there are some really cute ideas out there!
I bought the NoteCube and customized the notes that go into for him. Him and I are sappy with one another and we like keepsakes. I have no clue what he is getting me but I am sure it will be very special and from the heart.
We will also be handwriting letter to each other to read that morning.
My husband golfed the morning of our wedding with his groomsmen and few other friends of his so I got him a new set of golf clubs he'd been eyeing and had it set up at the golf course for him when he got there that morning; with a little help from his good who took them there for me.
He got me a new diamond necklace that I wore with my dress the day of our wedding. He had his sister give it to me with a note while we were getting ready.