Remember Newton: “If I have seen further it is by standing on the shoulders of giants.”
Your work comes from somewhere. Whatever your contribution, it stands on the shoulders of other researchers. How many papers are in your bibliography? How many more have you read, which didn’t make it into your bibliography but which informed your development or your work’s development?
By the end it might be almost impossible to remember every paper that has helped or influenced you. But you can reflect on your thesis and think about the meaningful fraction that makes up the core of what you’ve done. If you have 200 papers, what’s the top 10? The top 20?
Your thesis is built on a great body of work. What makes up the skeleton?