Scratch

It depends on what you mean by a highscore list. To make one in the game, you'll have to re-upload the project with a changed list every time someone posts a score. In scratch 2.0 highscores can automatically be saved in an online database.

In order to prevent having to re-upload the project so often, you can post a highscore list in the project notes and change it every time someone posts a score.

Unfortunately, there is no way to have high scores be submitted automatically until Scratch 2.0 is released.

I hope this helps!