[MOD NOTE: The project of adding PDF links for every book has been discontinued. When you use a link, look for the PDF notice at that site.]
(bismillah)
(salam)
People want to discuss and learn. Here is a list of books, in no particular order, that might be useful.
Akhlaq e-A'imma, Morals & Manners of the Holy Imams AS. Get PDF
http://www.al-islam.org/akhlaq-al-aimma-morals-manners-holy-imams-maulana-sayyid-zafar-hasan-amrohi
Ethics and Spiritual Growth. Get PDF
http://www.al-islam.org/ethics-and-spiritual-growth-sayyid-mujtaba-musawi-lari
Jami' al-Sa'adat (The Collector of Felicities). Get PDF
http://www.al-islam.org/jami-al-saadat-the-collector-of-felicities-muhammad-mahdi-ibn-abi-dharr-al-naraqi
Moral Values of Qur'an, a Commentary on Surah Hujurat. Get PDF
http://www.al-islam.org/moral-values-of-quran-tafsir-hujurat-ayatullah-dastaghaib
Code of Ethics for Muslim men and women. Get PDF
http://www.al-islam.org/code-ethics-muslim-men-and-women-sayyid-masud-masumi
Qalbe-Saleem, Immaculate Conscience. Get PDF
https://www.al-islam.org/qalbe-saleem-immaculate-conscience-ayatullah-sayyid-abdul-husayn-dastghaib-shirazi
Adabus Salat, The Disciplines of the Prayer. Get PDF
http://www.al-islam.org/adab-as-salat-disciplines-of-prayer-second-revised-edition-imam-khomeini
Self Building, An Islamic guide for Spiritual Migration towards God. Get PDF
http://www.al-islam.org/self-building-ayatullah-ibrahim-amini
Spiritual Discourses. Get PDF
http://www.al-islam.org/spiritual-discourses-murtadha-mutahhari
al Siraj: The Lantern on the Path To Allah Almighty. Get PDF
http://www.al-islam.org/al-siraj-the-lantern-on-the-path-to-Allah-almighty-husain-ibn-ali-ibn-sadiq-al-bahrani
The Elixir of Love. Get PDF
http://www.al-islam.org/the-elixir-of-love-muhammad-rayshahri
Awsaf al Ashraf, The Attributes of the Noble. Get PDF
http://www.al-islam.org/al-tawhid/vol11-no3-no4/awsaf-al-ashraf-attributes-noble-shaykh-khwaja-nasir-al-din-al-tusi
Last Will & Testament. Get PDF
http://www.al-islam.org/wasiyatnama-last-will-testament-ayatullah-shaikh-abdulla-mamkani
Diseases of the Soul. (No PDF link. Can download at the site.)
https://www.al-islam.org/nutshell/diseases_soul/
Anecdotes of the Ahlul Bayt. Get PDF
http://www.al-islam.org/anecdotes-ahlul-bayt-ayatullah-murtadha-mutahhari
Jihad al-Akbar, The Greatest Jihad: Combat with the Self. Get PDF
http://www.al-islam.org/jihad-al-akbar-the-greatest-jihad-combat-with-the-self-imam-khomeini
Struggle against the Self (jihad al-nafs). [PDF only]
https://www.al-islam.org/nutshell/files/jihad.pdf
Du’a (Supplication). Get PDF
http://www.al-islam.org/dua-supplication-sayyid-zafar-hasan-amrohi
Sexual Ethics in Islam and in the Western World. Get PDF
http://www.al-islam.org/sexual-ethics-islam-and-western-world-ayatullah-murtadha-mutahhari
Principles Of Marriage & Family Ethics. Get PDF
http://www.al-islam.org/principles-marriage-family-ethics-ayatullah-ibrahim-amini
Rafed.net Ethics articles:
https://en.rafed.net/index.php?option=com_content&view=category&id=78&Itemid=843