What are al-Raqāʾiq (teachings that soften the heart), and what are their chapters, branches, and contents, and what is the most comprehensive book on them, ancient and modern?

"Raqāʾiq" refers to books and topics that soften hearts, promote asceticism regarding worldly life, encourage desire for the Hereafter, urge obedience, and deter from disobedience. Among the books authored in this genre are: Az-Zuhd war-Raqāʾiq by Ibn al-Mubarak, Shuʿab al-Iman by Al-Bayhaqi, At-Targhib wat-Tarhib by Al-Mundhiri, Riyad as-Salihin by An-Nawawi, Mukhtasar Minhaj al-Qasidin by Al-Maqdisi, and the Nadrat an-Naʿim Encyclopedia, as well as other books by Sheikh al-Islam (Ibn Taymiyyah), Ibn al-Qayyim, and Ibn Rajab.