You might be using Gmail a lot without actually realising how useful it can be – especially as a taskmaster.
If you just want a simple to-do list with no bells and whistles, go to your Gmail account, and then click on the logo in the upper-left hand corner of the screen. There, you should see the ability to select “tasks”.
The task list will allow you to create a to-do list and then review it every day. You can also set Tasks up to sit on the left-hand side of the screen, so you see them whenever you log in.