Is there a specific supplication reported from the Prophet (peace be upon him), or the Companions, or the Tabi'een, for purifying one's liability, for someone who fears that some rights of others may remain due from him, which he has forgotten or overlooked, and he supplicates to his Lord that nothing remains due from him during his life and at his death?

The rights of people are great and are based on strict accountability, unlike the right of Allah, which is based on leniency. A martyr may be forgiven for every sin except debt. Whoever owes a debt must strive diligently to repay it, and Allah does not burden a soul beyond its capacity. Among the authentic supplications for settling debts are: "O Allah, suffice me with Your lawful provisions against Your unlawful ones, and enrich me by Your grace, independently of anyone besides You," and the supplication: "O Allah, Lord of the seven heavens... settle our debts for us and free us from poverty," and the supplication: "O Allah, Possessor of Sovereignty... have mercy on me with a mercy that makes me independent of the mercy of anyone besides You."