5:31
Then sent Allah a crow, it (was) scratching in the earth to show him how to hide (the) dead body (of) his brother. He said, "Woe to me! Am I unable that I can be like this [the] crow and hide (the) dead body (of) my brother?" Then he became of the regretful.

10:54
And if that for every soul (that) wronged, whatever (is) in the earth, it (would) seek to ransom with it, and they (will) confide the regret when they see the punishment. But will be judged between them in justice, and they (will) not (be) wronged.

34:33
And will say those who were oppressed to those who were arrogant, "Nay, (it was) a plot (by) night and (by) day when you were ordering us that we disbelieve in Allah and we set up for Him equals." But they will conceal the regret when they see the punishment. And We will put shackles on (the) necks (of) those who disbelieved. Will they be recompensed except (for) what they used to do?

5:52
And you see those - in their hearts (is) a disease they hasten to them saying, "We fear that (may) strike us a misfortune." But perhaps Allah [that] will bring the victory or a decision from Him. Then they will become for what they had concealed within themselves, regretful.

23:40
He said, "After a while little surely they will become regretful."

26:157
But they hamstrung her, then they became regretful.

49:6
O you who believe! If comes to you a wicked person with information, investigate, lest you harm a people in ignorance, then you become, over what you have done, regretful.