First of all, if you don't have Google Chrome, get it. Firefox is cool, too, but Chrome is still the gold standard web browser.
Starting with a general list of extensions and then we can categorize later.
- The Great Suspender - Automatically suspends unused tabs to free up system resources.
- HTTPS Everywhere - From the Electronic Frontier Foundation, this will automatically try to go to the HTTPS version of a website instead of the HTTP, if it's a viable option.
- OneTab - Whenever you find yourself with too many tabs, click the OneTab icon to convert all of your tabs into a list. When you need to access the tabs again, you can either restore them individually or all at once. Can save 95%+ of your system memory.
- Scraper - Scraper gets data out of web pages and into spreadsheets. Select a table on a webpage, right-click, and select "Scrape Similar."
- Data-Miner - Similar to the above, but maybe better.
- Simple Scraper - Chrome extension that enables data extraction form websites
- Terms of Service; Didn't Read - Gives you a summary of how sketchy-or-not the Terms of Service are for a given site.
- Isometric Contributions - Gives a very cool-looking graph of GitHub contributions.
- Export for Trello - Take a Trello board, export it to Excel.
- JSONView - If you're interacting with JSON, this is a great extension to prettify it/validate it.
- uBlock Origin - Apparently the best ad-blocker there is.
- Let's Get Colorblind - "...uses an algorithm to map on-screen colors to what a user with colorblindness might see," according to this medium post.