This is a universal socket wrench. It does one function, but a whole bunch of sizes. I'm considering it a multitool.
It also slots into my Leatherman
I'm told it tends to round off bolts and isn't good for regular use, but the whole point of a multitool is to do a job poorly when you wouldn't otherwise be able to do it at all. If you really need to twist a bolt off or tighten it on some bike trail, I doubt you'll care about the rounding until after you're home safe with your bolt cutters and replacements.
Here's a Swiss+Tech Utili-key
Looks about the same size and shape as a real key, and features screwdrivers as well as a flat and serrated cutting edge.
Not really the most functional of #multitools but that means it'll sit on your keyring long after you've misplaced your other tools. It's there for you when you need one of its 6 functions.