Adobe Marketplace and Exchange
"Adobe's Marketplace is a central resource for finding tools, services, and innovations that supplement and extend your Adobe products. "
Aehancers is a community based site jam packed with scripts from the community of members
After Effects Scripts
AEScripts is a marketplace for high-end scripts and plugins for Adobe After Effects. Scripts help enhance and automate otherwise tedious functions. They can also help improve workflows and provide automated operations.
Creative Workflow Hacks
A very simple site offering a number of free After Effects scripts to speed up your workflow
Crgreen has several scripts to help speed up your workflow
Motionscript is a helpful resource for learning how to create your own customized scripts