Just about any device for refining psychoactives... Alcohol stills, for one. We run one at home in TX, legal now, but which would have been jailbait in my grandmere's time. In certain parts of TX, wirecutters used to be illegal on strangers. They implied cattle rustling, etc. Phone recording equipment is legal now in many areas - formerly forbidden by wiretap laws, but now available through catalogs like Damark, etc. It would be so easy to find counter examples - non-weapon, physical items formerly legal, now illegal or heavily watched/licensed... precision scales, lab glassware, Kevlar, radio transmitters... pacoid.