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See this post listing many of the Salesforce extensions Useful Google Chrome Extensions for Salesforce/
Users
- Lazarus
- Single Click for Google Apps (yeah, not a Salesforce extension but gives you back your missing black bar functionality in Gmail).
Admins
- Salesforce.com Sandbox Favicon
- Salesforce.com id Clipper
- Salesforce.com Enhanced Formula Editor
- Quick Login As - log in as other users in your Salesforce Org.
- Grey Tab - OMG, how cool is this app - never be without it. I always add "system" type fields to the page layout and clutter up the page layout. This tool just shows every field.
- It even shows the full HTML of rich text fields!
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