I sometimes like getting a store kit as a starter, and then enhancing from there. Mostly, because such a kit will have a bag or container. Best one I ever found is a road emergency kit.
In a plastic molded case, about the size of a briefcase, it had a full socket set and ratchet, pliers, socket screwdriver set, siphon pump, collapsing water jug, jumper cables, road flares, glow sticks, bungees and ties, spare fuses, a thermal blanket, etc. I added in some specific fuses to my truck, and some spare bulbs of various kinds, and a pen LED flashlight, but other than that, was a well put together kit.
Most cheap first aid kits are a pretty good start, but you usually have to add a tube of antibacterial ointment, some butterfly bandages, and an Ace bandage, as well as some OTC (Over The Counter) and other meds.