My Dad was Inspector Gadget the Wizard
You have inherited one piece of old world technology. It should be portable, somewhat small, magic or tech oriented, and nothing crazy like a repeating laser gun with inifinite ammo or something! Some examples will follow below, but if you have an idea please talk to your friendly Neighborhood DM about it!
- Nuclear powered flashlight, can be attached to armor/clothes/helmet etc and has different modes, as well as a flashbang blind attack (1/day)
- Night vision goggles with a thermal scan mode (requires power 1 SEU per day)
- Prototype Portable geo-thermal generator. Small unit, if dug into the dirt/mud (aka no stone/metal/hard ground), will generate small amounts of power and heat. Enough to keep a tent warm even on the cold side of Ayr. produces 5 SEU per long rest, and can be used to recharge equipment, batteries, ammo cartridges etc (but not Aether Coins)