
Small and simple but useful tools (specially but not limited) for Windows and .Net platforms:
Paint.Net: May be useful as claimed to cover 80% of Photoshop features.
Resource Monitor: What's going in Windows, built-in feature, just click the button on Performance tab of Windows Task Manager.
FireBug:Scott Hanselman calls this x-ray into browser.
There is more to explore in the link
Posted Link in Programming