Snap Key Options

Selected: Specifies to snap keys only from the currently selected objects.
All: Specifies to snap keys on all objects, including objects that you can’t usually select from the scene view (such as construction history nodes).

Hierarchy: Specifies how keys in the selected keyset will be snapped from a hierarchy of grouped or parented objects.

Selected: Specifies that the keys to be snapped will include only the keys on the currently selected object. Default is on.
Below: Specifies that the keys to be snapped will include the keys on the selected object and all the objects below it in the hierarchy. Default is off.

Channels: Specifies the channels (keyable attributes) whose keys will be snapped.

All Keyable: Specifies that the keyset will include the animation curves of all keyable attributes of the selected object. Default is on.
From Channel Box: Specifies that the keyset will include the animation curves of only those channels currently selected in the Channel Box. Default is off.

Driven Channels: Specifies that the keyset to be snapped will include any driven keys. The driven keys enable the values of keyable attributes (channels) to be driven by the values of other attributes. See Driven keys. Default is off.
Control Points: Specifies whether the keyset to be snapped will include all the animation curves of a selected deformable object’s control points. Control points include NURBS control vertices (CVs), polygonal vertices, and lattice points. Default is off.
Shapes: Specifies whether the keyset to be snapped will include the animation curves of a selected object’s shape node as well as its transform node. Typically, when you directly select an object in the workspace (for instance, in the perspective view), what is selected is the object’s transform node. To snap the animation curves of the object’s shape node as well as its transform node, be sure Shapes is on. To snap the animation curves of the transform node only, turn Shapes off. Default is on.
Time Range: Specifies the time range of the keyset’s animation curves.

All: Specifies no limit on the time range.
Start/End: Specifies a time range from Start Time to End Time.
Time Slider: Specifies a time range defined by the Playback Start and End times of the Time Slider.
Start Time: Specifies the start of the time range (available if Start/End is on).
End Time: Specifies the end of the time range (available if Start/End is on).

Snap Times to Multiple of: This value defines multiples of the time unit to snap to.
Snap Values to Multiple of: This value defines multiples of whole number attribute values to snap to.