HDMI's not USB. The speaker jack is usually not USB. An external webcam with a bandaid over it to block it is really not much more useful than the built-in webcam with a bandaid over it.
External DVD, yes, if the laptop doesn't have one built in (my wife's ultra-portable doesn't; my work laptop does.) No, if there's a built-in, unless you really need the blu-ray burner. And yes, external hard drive sometimes (USB3 are becoming common enough these days, but there was a while you might use E-SATA instead.)
I'd prefer mouse and keyboard to connect over Bluetooth rather than USB, but most "wireless" mice and keyboards insist on using their own USB-frob to actually connect to the device, running whatever random standard or non-standard.