-Flamable liquids, i.e. petrol & kerosene.
Petrol pumps at gas stations should work like a mounted weapon, limited by the length of the pipe, it would have a range of about 10ft, allowing you to spray liquid over cars & the forecourt.
-Petrol cans can be another weapon allowing you to take your pyromania on the road & douse buildings, cars & peds in petrol.
-Lighters for starting camp fires, lighting a gas stove or of course for helping out a ped smoker who's been caught short.
-Handcuffs & or rope to make hostage/prisoner taking easier.
-Showroom cars should have prices displayed on them. Those in second hand car showrooms should have stickers in the windshield, which are only removed when the car is purchased legitimately or at least taken to a pay 'n' spray.
-Monster trucks & tanks should drive over & crush cars in a realistic manner, not necessarily blowing them up.
-Convertables including electric soft & hard top models.
-More unique/customised ped vehicles e.g. Boy racer modifications, stretch hummer, Limo with a hot tub on the back.
This could also include film/TV inspired bonus vehicles, KITT, the A-team van, The General Lee, various Bond cars, Batmobile & of course a Batcave under your mansion, complete with turntables on which you can display them.