best plugins for firefox

1. Privacy and Security
uBlock Origin: A lightweight yet powerful ad and tracker blocker that helps enhance privacy and browsing speed.
Privacy Badger: Created by the Electronic Frontier Foundation (EFF), it automatically blocks trackers that monitor your online behavior without your permission.
HTTPS Everywhere: Ensures you're using HTTPS (a more secure version of HTTP) whenever possible to protect your data and browsing activity.
NoScript: Gives you full control over which scripts run on websites, helping prevent unwanted or malicious code from executing.
2. Productivity
LastPass / Bitwarden: Password managers that store and auto-fill passwords across websites, making logins secure and easy.
Grammarly: Helps you write clearly and error-free by providing grammar and spell check as you type across different websites.
Pocket: Owned by Mozilla, Pocket allows you to save articles, videos, and web pages for later viewing.
Tree Style Tab: Transforms your tabs into a vertical tree structure, making it easier to manage a large number of tabs.
Tab Stash: A tab manager that lets you save and organize tabs into groups, decluttering your browsing session.
3. Customization
Stylus: Enables you to apply custom CSS styles to websites, letting you tweak the look and feel of your favorite sites.
Dark Reader: Applies dark mode to any website, reducing eye strain and making browsing more comfortable at night.
Enhancer for YouTube: Adds many useful features to YouTube, like ad skipping, adjustable playback speed, and customization options for video controls.
4. Developer Tools
Web Developer: A toolbar packed with web development tools, including options to inspect elements, disable JavaScript, and more.
Wappalyzer: Identifies technologies used on websites, such as CMS, analytics tools, frameworks, and more.
Firebug (Legacy, replaced by Firefox Developer Tools): Offers robust debugging and performance analysis tools.
5. Shopping and Deals
Honey: Automatically applies coupon codes when shopping online, helping you find discounts and deals with ease.
Rakuten: Offers cashback on your purchases from participating stores when shopping online.
6. Media Downloaders
Video DownloadHelper: Allows you to download videos and images from websites like YouTube, Vimeo, and Dailymotion.
DownThemAll!: A powerful download manager that lets you download files in bulk from websites.
7. Miscellaneous
SponsorBlock for YouTube: Skips sponsored segments in YouTube videos automatically, enhancing your viewing experience.
Decentraleyes: Protects your privacy by emulating content delivery networks (CDNs) locally, reducing the need for third-party connections.
Bookmark Organizer: Helps keep your bookmarks organized and free of duplicates, making them easier to find.

As stated above, uBlock Origin is a really great adblocker for Firefox. If you want even more security, you can use LocalCDN to increase privacy.