I have found a few Youtube channels that have more than one helpful video. So, I figured this thread could be where we post one video but recommend that others look at more on the channels.
This channel has good examples of idioms and easy-to-understand explanations of them: https://www.youtube.com/watch?v=xLSpInYhzYw&list=PLItVCkPXPy9Yie_JOKkzflnpXZcjdQPqx&index=2
This channel goes over the differences in the pronunciation of IPA (International Phonetic Alphabet). I recommend this for higher-level classes. Some students may be familiar with IPA, while others may not be. So, a quick explanation or survey of familiarity might be needed. If no students, or the majority of students, are not familiar with IPA, it might not be a good idea to use these, because it might be too confusing. It's up to you to decide, of course. https://www.youtube.com/watch?v=qDego-Mt1W0&list=PLItVCkPXPy9Yie_JOKkzflnpXZcjdQPqx&index=13&t=54s
This is a great find! I agree with your assessment that it should be for the higher levels for the most part.
The idioms videos have a great explanation, but first go over the history and evolution of the phrase and its use- great for conversation groups and warm ups in High Intermediate/Advanced.
The pronunciation guide could be used for lower levels. I wouldn't recommend showing the videos to the students, but a teacher could review the video and then go through it in the class with very specific examples. For example, Basics, Low Beginner, High Beginner - when reviewing the alphabet and different sounds, stick to very specific examples with the letter and sound corresponding. In Low Intermediate, High Intermediate, and Advanced, going over the words that have the sound but not the same letter provided would be ok. High Intermediate and Advanced could go through the whole list and examine all the words and the whys that are in the video.