The most useful thing after socket sets for the occasional use? AA powered 6V Black & Decker screwdriver.
For running on 4 AA batteries, this has worked better for me for years than I could have imagined. I first got one of these over 15 years ago when I was working to remove half-stripped #3 Phillips screws off of 30-40 year old UJM controls. It had the perfect amount of steady torque to allow the screw reverser to stay engaged and slowly back things out. Since then, I've always had one around the house.
I could go rechargeable, but that's just another charger I'd have to keep around. For how often I use it and how long batteries last, it's not worth the hassle to have another cord hanging around that I'm just going to lose at the worst possible time.
Meh, probably for my setup, but Black & Decker AD600 6-Volt Alkaline 1/4-Inch Hex Cordless Drill/Driver with Accessory Assortment https://www.amazon.com/dp/B000077CPQ/ref=cm_sw_r_awd_.TJAvb1AHRXV5
And
Hario Ceramic Coffee Mill Skerton Storage Capacity (100g) https://www.amazon.com/dp/B001802PIQ/ref=cm_sw_r_awd_gVJAvb1XXVE86
Is $60!
I forgot
Capri Tools CP10111 Capri Tools 1/4-in Keyless Drill Chuck, Black https://www.amazon.com/dp/B00V3X385M/ref=cm_sw_r_awd_2WJAvb05A9D4F
Still close to the $60 mark
Unless you already have a drill