The VSCode Dimmer extension is great when you want to show and explain code to someone. It helpfully dims the code that's not relevant to the selected line, making it easier for your audience to focus on what you want them to.

Use VSCode Dimmer to Highlight Code when Teaching

The better-comments extension lets us specify different types of comments and color them accordingly. This lets you add semantic meaning to your comments, for example: you can mark some comments as TODO, and others as important, or as questions. You can also define your own custom types of comments.