- Lighters can be useful. I own numerous movie-featured ones that could be used every day (I don't smoke, so I don't need anywhere near that many). I just got one from Inglourious Basterds (1936 Zunder 1000 lighter from the Berlin Olympics a few years before WWII), for example.
Other lighter examples:
There's Elsa's Lucky Zippo from Last Crusade, Marion's IMCO Super 6700 from Raiders, the Colibri Moelectric 88 from The Man With The Golden Gun, the Dunhill Unique (from Russia With Love and The Roaring 20s and the Unique Sport model in Die Another Day), The Colibri lighter Rachel uses in Blade Runner, etc. etc.
- I've got two knives from Indiana Jones (Indy's knife from Raiders and Mutt's knife from Crystal Kingdom) that are the real thing.
- There are functional sword replicas (from Conan and other movies) (not sure how 'useful' they are in this day and age, but you never know).
- I've got whiskey bottles and glasses from Indiana Jones movies and Blade Runner 2049. I use some for display and use the others as functional glasses.
- I've got functional hats from Indiana Jones and old Bogart movies (and the Indy Jacket and whip)
-You could also get things like classic cameras used in movies (e.g. My Canon F-1 the character Sue Charlton used in Crocodile Dundee) that could be used every day (yes you can still get 35mm film).
-There's also replica working guns for those that live in countries that are allowed to collect them (e.g. Indy's S&W M1917 Revolver or Browning HP from Raiders of the Lost Ark, for example).