You can actually skip favors if you want! They’re not a necessity. If you decide to give them though go with something edible
I agree with the pee pee and that favors are constantly mentioned in list of things that guests will not miss it a wedding. Only provide them if you want to but for me your safest bet is something edible. You could do like some personalized M&Ms or Hershey's Kisses. I know for me I'm not a fan of symbolic gifts but I'm never going to turn down something food-related or even mini bottles of alcohol.