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
"XScriptorium allows you to store your favourite expressions, scripts, presets and AE projects. You can do so through one of three methods: Upload Content, Link to Content and Upload Private Content"