While I only remember two from the class, I’ve been collecting my own エアバッグ表現 ever since I learned the term.
I would put the following two terms in the same category: 〜ですが and 〜の件ですが. Both serve as a warning that you are about to address a certain subject, and with the right intonation and a slight pause after the が, you can convey the idea that you are about to raise a touchy subject. 件 literally means subject. For example, an interviewer might say:
Both serve as a warning that the administrative office fees or declining birth rate will be the topic, giving the interviewee a small amount of extra time to organize his thoughts.
悪い（わるい）ですが is kind of the Japanese way of saying, “My bad” preemptively. 悪かったです is the way you would do a true “My bad.” I believe I used it successfully the other day in Himeji Station – 「悪いですが、両替（りょうがえ）もらえますか。」I was trying to store some luggage in a locker, but, as is often the case, there was no change machine. I approached a bento lady and said, “Sorry to ask, but could you change this bill?” She gave me a kind of reproachful grin but then handed me the coins anyway. Robin told me that he was yellow carded for inappropriate usage of 悪いですが. Apparently, it is used for people beneath you in the Japanese social hierarchy, so perhaps the lady was just pissed off that I was talking to her as though I were her boss. It does smack of someone in an authority position would use to explain slacking or some other mistake, so use with caution.