Track View > Curve Editor > Track View toolbar > Move Keys flyout > Move Keys, Move Keys Horizontal, or Move Keys Vertical
With the Move Keys flyout buttons in the Curve Editor, you can move one or more highlighted keys to change keys' timing, values, or both.
You can clone keys by holding down Shift while dragging. The new keys are added to the existing keys on the curve.
You can also clone keys to replace existing keys by holding down Shift+Alt while dragging.
Tip: When you select keys to clone and replace others, you can include the key before the first selected key to preserve the tangent of your first copied key.
To move a selection of keys:
In the Hierarchy list, highlight one or more tracks.
Only keys in highlighted tracks appear in the Key window.
By default, the Move Keys button is yellow, showing it is already on.
Drag the highlighted keys to a new location, or press Shift and drag the highlighted keys to add copies at the new location.
Press Shift+Alt, and drag the highlighted keys towards existing keys to replace them with copies.