Quantity   Component name
1 × Negative ion generator components There is quite a variety of suppliers out there. Have tested several 12VDC varieties and found that all of those that use small carbon-fiber brushes for output, gave very close to exactly the same output per brush.
1 × Drok DC voltage converter/regulator, wide range of input, 5 VDC output. One of the rigs is lower-power, doesn't need the tight control; one of them needs it, and it uses a Drok DC buck (not boost) 5VDC voltage regulator.
1 × Fuse tap. This adds a circuit and a fuse to a vehicle's fuse box.
1 × Temperature-controlled switch. You might be amazed if you google using the description and the part "XH-W3001". Many vendors in many places, and it's a great part.