Source Material

Holy Bible (ESV) - https://www.esv.org/.
Holy Bible (KJV) - https://www.kingjamesbibleonline.org/.

The Book of Mormon, Doctrine and Covenants, Pearl of Great Price (online).

Book of Mormon - Teacher's Manual - 2012 (html online).

Catechism for Children (online, 28 mb PDF file).

Coming of the Lord (online) - a look into the LDS future.

Dictionary of Gospel Topics (online, alternate).

Discourses of Brigham Young (online).

Doctrine and Covenants and Church History - Gospel Doctrine Teachers Manual (1999, online).

Gospel Doctrine - by Joseph F. Smith (1919, online, mirrored site).

Gospel Fundamentals (2002, online).

Gospel Principles (1997, pdf).
Gospel Principles (2009, html).

History of the LDS Church, 1902, 7 volumes (text online, vol 1, vol 2, vol 3, vol 4, vol 5, vol 6, vol 7).
Text files compressed (vol 1, vol 2, vol 3, vol 4, vol 5, vol 6, vol 7).

Jesus the Christ - by James Edward Talmage (1922, online).

Journal of Discourses (online).

King Follett Discourse: part 1 - April 1971 Ensign, part 2 - May 1971 Ensign

King Follett Discourse: A Newly Amalgamated Text (BYU)

Magazines - Liahona, Friend, Ensign, Youth (online).

Nursery Manual - Behold Your Little Ones (2008, online).

Preach My Gospel (2004, online).

Preparing for Exaltation: Teacher's Manual (1998, online).

Religion 121-122 - Book of Mormon Student Manual - 2009 (online).

Religion 225 - Foundations of the Restoration Teacher's Manual (2015, online).

Religion 234–235 - Eternal Marriage Student Manual (2001, online).

Religion 301-2 - Old Testament Instructors Guide (1982, online).

Religion 327 - Pearl of Great Price - Student Manual (2017, online).

Religion 327 - Pearl of Great Price - Teachers Manual (2017, online).

Religion 341-343 - Church History in the Fullness of Times Student Manual (2003, online).

Religion 345 - Presidents of the Church Student Manual (2003, online).

Religion 430-431 - Doctrines of the Gospel Student Manual (2004, online).

Songs - A collection of sacred hymns for the Church of Jesus Christ of Latter-day Saints in Europe (online, 9 MB PDF).

The Way to Perfection (1931) - former LDS President Joseph Fielding Smith (online, PDF).

Teachings of Presidents of the LDS Church (in PDF format):
     Joseph Smith - 1938 (online, mirrored site).
     Joseph Smith - current (online).
     Brigham Young (online).
     John Taylor (online).
     Wilford Woodruff (online).
     Lorenzo Snow (online).
     Joseph F. Smith (online).
     Heber J. Grant (online).
     George Albert Smith (online).
     David O. McKay (online).
     Harold B. Lee (online).
     Spencer W. Kimball (online).

True to the Faith - topics in alphabetical order (online, mirrored site).

Word of Wisdom pamphlet (mirrored site).

The Plan of Salvation - 2008 (online).

The Restoration - 2008 (online).

The Gospel of Jesus Christ - 2008 (online).

The majority of LDS teaching manuals can be found at these sites:

https://www.churchofjesuschrist.org/si/institute/manuals/?lang=eng
https://www.churchofjesuschrist.org/si/seminary/manuals/?lang=eng