I have been working on a commentary on the Psalms. I have decided to compile some helpful links that I discovered during my research. It includes a mix of exegetical and sermonic links. Here is what I have for Psalm 51 (in no particular order). Feel free to mention any that you find helpful in the comments section.
Ray Stedman., “How to Handle a Bad Conscience,” Psalm 50: https://www.raystedman.org/old-testament/psalms/how-to-handle-a-bad-conscience
Analysis by C. J. Labuschagne: https://www.labuschagne.nl/ps051.pdf
John MacArthur sermon: https://www.gty.org/library/sermons-library/80-353/the-believers-confession-of-sin
William Barrick’s notes: https://drbarrick.org/files/studynotes/Psalms/Ps_051.pdf
The Fathers on Psalm 51: https://pursuingveritas.com/2019/09/17/the-fathers-on-psalm-51