Most productivity extension lists are padded with sponsored picks and tools that collect your browsing history. This list is different: every extension here is free, well-audited or open source, and does one specific thing better than anything else in its category. All work in Chrome and most in Firefox.
Ad & Tracker Blocking
uBlock Origin — Essential
ublockorigin.com is the gold standard for content blocking. It's open source, uses minimal memory compared to other blockers, and blocks ads, tracking scripts, and malware domains by default. Unlike most blockers, it has no "acceptable ads" program that pays to whitelist certain advertisers.
Install it, leave the defaults on, and you're done. Advanced users can add extra filter lists or use element picker to block specific page elements that slip through.
Note for Chrome users: Google's Manifest V3 transition has weakened some extensions' blocking capabilities. uBlock Origin Lite is the MV3-compatible version available in the Chrome Web Store for Chrome 127+; the full uBlock Origin continues to work in Firefox.
Tab Management
Workona Tab Manager (free tier)
workona.com groups open tabs into named workspaces — "Research," "Client X," "Personal" — and lets you switch between them instantly. Tabs in inactive workspaces are suspended, reducing memory use. The free tier allows up to five workspaces, which is enough for most people.
If you regularly have 30+ tabs open across different projects, this is the single highest-impact extension for focus and browser speed.
OneTab — Simpler alternative
OneTab (free, open source) does one thing: it collapses all your open tabs into a single list page, freeing memory immediately. You can restore individual tabs or all of them at once. No account needed, no cloud sync — everything stays local. Good for people who just want to deal with tab sprawl without a full workspace system.
Reading & Clipping
Omnivore — Read-it-later with full text search
omnivore.app is an open-source read-it-later service with a browser extension, iOS/Android apps, and a clean reading view that strips ads and sidebars. Unlike Pocket (now owned by Mozilla and declining), Omnivore lets you search the full text of everything you've saved, add highlights and notes, and export your library. Free with no paywalled reading features.
Writing Assistance
LanguageTool
languagetool.org checks grammar and style in any text field in your browser — emails, forms, Google Docs, web-based editors. The free tier covers basic grammar and spelling in 30+ languages. Unlike some competitors, it has a clear privacy policy and offers a self-hosted option for sensitive documents.
It's not as aggressive as Grammarly about upselling, and the free tier is genuinely useful rather than a tease.
Distraction Blocking
LeechBlock NG
proginosko.com/leechblock is a free, open-source site blocker for Firefox and Chrome. You define lists of sites to block and the time windows when blocking applies — for example, block Reddit and YouTube from 9am to 6pm on weekdays. It's more configurable than most paid alternatives and has no account requirement.
Setup takes 10 minutes. The key is configuring a lockout password that you don't have memorized — stored in your password manager, say — so disabling the block requires deliberate effort.
Screenshots & Annotation
Awesome Screenshot & Screen Recorder
Captures full-page screenshots (including content below the fold), lets you annotate with arrows, boxes, and text, and can record short screen clips. The free tier covers everything most users need. Works in Chrome and Firefox.
Alternatively, FireShot (free) focuses purely on full-page screenshots with no recording, and saves directly to PNG or PDF — no sign-in required.
What to Avoid
Some widely-installed extensions are worth staying away from:
- Honey / PayPal Rewards: Analyzes every page you visit and has a history of attribution manipulation. The coupon savings rarely exceed what checking RetailMeNot takes.
- Any "free VPN" extension: Free VPN extensions typically sell your browsing data to cover their costs — the opposite of what a VPN is supposed to do.
- Extensions with broad permissions and no clear use case: If something asks to "read and change all your data on all websites" and isn't a content blocker or password manager, remove it.
The Short List
- Must-have: uBlock Origin (blocking), your password manager
- If you have tab sprawl: Workona (5 workspaces free) or OneTab (local, no account)
- For reading: Omnivore
- For writing: LanguageTool
- For focus: LeechBlock NG
Five to seven extensions is about the right number for most people. More than that and the overhead — permissions, update surface, memory — starts to outweigh the benefit.