I agree that bridge and middle 8 are nearly the same if not identical. Perhaps bridge is an overall common term, and middle 8 was specialized for pop music, as The Beatles like to call it that as the device in their hit songs. However, a middle 8 by definition is 8 bars, whereas a bridge is not defined or limited IMO.
A pre-chorus is a lead in to the chorus. It will have the same lyrics in each pre-chorus usually, so it's like a chorus structure (as opposed to verse sections that typically change lyrics each time). It's usually an energy shift from verse but less intense than the chorus, so it builds excitement and helps set up the message of the chorus. That can be for a song energy or lyric device standpoint.
There are some other devices, such as "stops" and "turnarounds" and perhaps many others. Those are more for musical effect but help create energy shifts and transitions in songs. A stop brings a dramatic pause in the tempo, and can be lots of fun. A turnaround can be many things, but is very common in blues. They can be one or two measures, usually short. In blues, it may be a cool riff inserted between 12-bar progressions, which can be pretty vanilla and cliche.