NoScript
Open Source
NoScript for Firefox pre-emptively blocks malicious scripts.
Kill Evil
Open Source
Prevent printing, selection spying, unwanted tabs, etc.
RequestPolicy
Open Source
RequestPolicy is a open source Firefox extension to control cross-site requests.
Better Pop Up Blocker is a browser extension for popup blocker.
Compare Flashblock with alternatives
Compare NoScript and Flashblock and decide which is most suitable for you.
Compare RequestPolicy and Flashblock and decide which is most suitable for you.
Compare Kill Evil and Flashblock and decide which is most suitable for you.
Compare Better Pop Up Blocker and Flashblock and decide which is most suitable for you.