SimpleScrollBar
From the site:
Here’s an AS3 class that creates a simple scroll bar. Set this as the Base Class for any movie clip. The container clip must have two movie clips named drag_mc and track_mc. These clips act as the dragger and track for the scroll bar
Add an event listener to call a handler when the scroll bar is dragged. SimpleScrollBar dispatches the ScrollBarEvent.UPDATE which includes the property scroll_value. This property holds a value from 0 to 1 representing the position of the dragger.
http://www.webdevils.com/?p=84
LetSnow Flash Snow Effect Component (as3)
LetSnow Flash Snow Effect Component (as3):
LetSnow Flash Component Info
LetSnow Flash Component is a standard extension for Adobe Flash CS3. You simply install the MXP file and then you just drag & drop the extension from the Components panel onto the scene of your movie. The component can be used in a movie with any structure. You can control the component to create snow effect.
Component Features
We have built our component to be easily customizable and easy to use. You can set the size of the snowflakes, the power of the wind, the amount of gravity, and many other parameters.
Online Demo:
http://www.letsnow.net/demo.html
Documentation (parameters):
http://www.letsnow.net/documentation.html
Reflection Component
The reflection component is used to give the illusion of a reflective surface in your Flex 2 applications. It includes a few properties for custom fading, skewing and scaling and was made with real-time reflection in mind. This component is a little different from similar work like Trey Long’s or PixelFumes’ because its not used like a filter or effect and takes up its own screen real estate.
http://labs.atellis.com/2007/07/11/atellis-reflection-component/
StyleCollection for CS3 Components
From the site:
The StyleCollection class lets you create groups of styles that are applied to and automatically updated on subscribing components. It supports both instance and renderer styles (setStyle and setRendererStyle respectively), and uses component introspection to apply only relevant styles to each component. StyleCollection exposes a robust interface, including a static interface that provides global access to named styles.
 http://www.gskinner.com/blog/archives/2007/06/stylecollection.html
HTMLStyle
HTMLStyle is a component I developed for the sake of simplifying the process of formatting html-text in Flex. It allows you to create a stylesheet pretty similar to the way you would place a mx:Style tag for declaring style definitions for your components.
The component also has a source property which can be set to target an external css file..
Check it out here:
rubenswieringa.com/blog/htmlstyle
SuperViewStack
From the site:
For a Flex project I’m working on I decided I would need a ViewStack that also showed the children underneath the selectedChild.
[...]
SuperViewStack by default displays all of its children that are underneath its selectedChild.
You can easily adjust the factor with which underlying children fade, and with what tint. It is also possible to switch back to normal ViewStack mode.
SuperViewStack has almost all of the functionality that ViewStack has, and all the child-methods (for example addChild()) are still functional.
rubenswieringa.com/blog/superviewstack
AS 2 Tree component with invisible background
Use a tree component with a transparent background.
http://jeff.mxdj.com/as2_tree_component_with_a_transparent_background.htm