I'm sure that others will add more of these, but an obvious one is at the end of the play. Once Othello has killed Desdemona and Iago has killed Emilia, Othello kills himself after realizing that he cannot live after killing an innocent Desdemona. Iago is too much of a coward and self-centered to kill himself after all of his dastardly deeds, so he is arrested and taken into custody once his schemes are revealed.
Also, Othello has meted out his own punishment for killing his innocent wife. He kills himself as his own punishment because he cannot live with himself for doing so and he cannot live with himself for shaming the country he has served in this manner.