The one were the wire is clamped down by the end of the screw is the one I described as a metal block with a hole for the wire. Hardly ever used for modern switches or receptacles, but very common for plugs.
Strip connectors can have virtually any color here. White, yellow, red, grey, blue, green, purple, black, clear,... using different colors in one box adds a touch of color to the installation, I often combinme blue, red and yellow.
