Is a small project like a to do list worth putting on a resume?

Answer 1

You should only put your most impressive ones on your resume, if a simple to-do list is one of the best ones you have then you can put it there also as it is much better than having nothing under the projects section.

Answer 2

If you think it is best of its type you should put it there.

It's not matter how small and easy your code is?
What actually matters is either it is impressive or not.
So analyse your code yourself and do as you wish.