BetterHandles gives you more control over Bezier curves in Adobe Illustrator.
Some features are:
Select multiple handles, and collectively move, extend, rotate, or retract them
Extend or retract handles without changing their angles
Edit points numerically: anchor, in handle, out handle
Convert multiple points from corner to smooth or vice versa
Automatically extend new handles on multiple points
Intuitively reshape path segments, optionally constraining handle directions
Use slow-drag to divide the cursor movement for extremely precise moves
Equalize a point's handles
See all the handles on a path while editing it
Split a path at one or more points
Delete one or more points and close the path around them
See when the cursor is over a handle, point, or path — without having to use Smart Guides.
And more!