- Biobar - a toolbar for browsing biological data and databases
- LSID extension enables resolution of lsidres URIs; the lsidres protocol is used by IBM's LaunchPad for Life Sciencer Identifiers (LSIDs)
- LSID Browser extension from IBM, SourceForge link
- bioFOX aims at implementing various bioinformatics tools as an extension on the Mozilla based browsers
- BioMed Central toolbar allows you to conveniently search BioMed Central, PubMed Central, PubMed, Faculty of 1000 and Google
- MIT LibX is a toolbar that allows you to quickly search the Barton catalog, Vera, Google Scholar, the SFX FullText Finder and other search tools
- HDL/DOI Protocol Handler for Mozilla
- Operator - a Microformat Detection Extension for Firefox 2; it demonstrates the usefulness of semantic information on the Web, in real world scenarios.
- Semantic Radar is a semantic metadata detector for Mozilla Firefox. It is a browser extension which inspects web pages for links to Semantic Web metadata and informs about presence of it by showing an icon in browser's status bar.
- Top FF2 config tweaks: set the network.prefetch-next key to false