MAXQDA - a professional software for qualitative and mixed methods data analysis
Swift Selection Search - Swiftly access your search engines in a popup panel when you select text in a webpage.
ATLAS.ti - ATLAS.ti is a powerful workbench for the qualitative analysis of large bodies of textual, graphical, audio and video data. It offers a variety of sophisticated tools for accomplishing the tasks associated with any systematic approach to "soft" data.
Trufflepiggy - Quick Search - The all-in-one search addon: just select and search. Find on multiple websites at once. Search via overlay, context menu or omnibar. Featuring anonymous profiles. Easy setup: select from 1000+ user generated searches. Cross-browser sync.
Taguette - A spin on the phrase "tag it!
Selection Search - With this extension you can easily search for text you have selected.