1. SoqlxSoqlXplorer is an awesome tool for developers using the Salesforce.com platform.
2. BeatboxBeatbox is an easy to use Python Library for accessing the Salesforce.com API
3. ZksforceCocoa library for calling the Salesforce.com Web Services API
4. json2apexGenerate strongly typed apex code from a json structure.
5. sf3Sync your Macs address book & calendar to Salesforce.com
7. maildropMaildrop provides an easy way to copy emails from Mail, Entourage & Outlook 2011 into Salesforce.com.