Our bar included baskets of:
-Marshmallows (regular, strawberry & chocolate/white swirl)
-Graham crackers (regular, cinnamon & chocolate)
-Chocolate (milk chocolate, dark chocolate & cookies 'n cream bars)
We also purchased some actual smore's sticks so our guests didn't have to forage in the woods for sticks, hah ;)
Here's some photos I found around the web for a little wedding s'mores inspiration. It can actually be really fun and even look super cute!
Love the various homemade mallows!
I also found a great tutorial for making s'mores kit as a wedding favor here, super adorable!