http://aescripts.com/animationpatterns

animationPATTERNS is a keyframebased easing assistance, that allows you to edit and create new easing types.
MatchRate
http://aescripts.com/matchrate

MatchRate is an After Effects script for extending a layer property's animation at the same rate.
Keyframe Presets
http://aescripts.com/keyframe-presets

Create presets for keyframes from multiple layers
Keysmith
http://aescripts.com/keysmith

This script provides methods to manipulate keyframes and property channels precisely in compact UI.
Bake Parented Transform
http://aescripts.com/bake-parented-transform

This script will take a parented layer and convert its motion into keyframes of an unparented layer suitable for exporting or similar use.
kd_AutoFade
http://aescripts.com/kd_autofade

Automatically fade, scale and rotate layers in and out.
Paste Multiple Keyframes
http://aescripts.com/paste-multiple-keyframes

This script will let you copy and paste keyframes from multiple layers at the same time.