The NPR One app used to chew through a few hundred mb of data in "caching" every time you started it. No way to restrict this function to wifi only. And no, you can't select bit rates.
Also Zoom has little ability to minimize the audio or video data usage (but I've learned you can reduce how much of others video is sent to you by reducing the window size). Just wish I could set myself to 480p to be present but not destroy my data while working at the cabin.