What are some examples of standing waves?
General: Strings and air columns. Specific: piano strings, clarinet, microwave standing wave (using metal sheet to reflect the wave and a portable receiver) and Ruben's Tube.
Often standing waves on strings are the starting point for learning about standing waves as you can see them. Then standing waves with sound in air columns and microwave standing waves can be covered. Sound and microwaves cannot be seen so interpreting observations from those experiments is more abstract.
If you haven't seen the Ruben's Tube before it is a great visualisation of standing waves. I took a video of it: