This will be a developing symbols reference as seen on headstones and other funerary monuments.
Angel
In general a heavenly being
Angel holding book and pen-Also known as the “Recording Angel”
Angel holding a staff and presenting as male-Father Time
Dove
In general represents purity, peace, and grace
A dead dove can represent a new beginning or heartache
Egg
In general represents the circle of life
Flower
In general represents the beauty of life
A wilted flower is often a symbol of a life cut short.
Handshake
Represents that the person was married when they passed.
Hourglass
Represents the marching of time
Interlocking links
Symbol for the Independent Order of Odd Fellows. The three links represent Friendship, Love, and Truth.
Knights of the Pythias
Often seen as K of P on headstones, it means the person was a member of the fraternal order, Knights of the Pythias
Star
Star of Bethlehem
A five pointed star can represent the wounds that Christ received during the crucifixition.
Triangle
In Christianity, it represents the Holy Trinity of Faith, Hope, and Charity
Repeating symbols of three can also represent this.
Wreath
Victory over death
If accompanied with someone who lost their life in battle, it represents their sacrifices will be remembered.
Wings
Represent a descent to heaven