Music suitable for preludes or to add variety when accompanying the congregation or choir.
M 12.8 = Hymn arrangements for organ by LDS composers
Example: Hymn Settings for Organ by Doug Bush (9 vols.) at M 12.8 .B87 H95 2007
M 14.18 = Variations and free harmonizations mixed in with regular organ accompaniments for hymns
Example: Hymn Additions (several volumes) at M 14.18 .H96 2010
M 14.4 and M 14.5 = Seasonal or special occasions (Christmas, Easter, Weddings) not specifically LDS
MT 180 = Instruction books for church organists, including hymn arrangements (not specifically LDS)
Regardless of call number, compositions by LDS composers are designated by a .8 after the call number (so, for example: M 2061.8, or M 2101.58).