New Tab & Toolbox Plus από 23WIN

A multi purpose Firefox extension that does all this & more:

• Set your Custom "Home Page" under Options, in this extension.
• Open that Custom Page in "New Tab" instead of the Home Page.
• Toolbar icon for easy access to Downloads, History, Bookmarks.
• Automatically force YouTube videos to play at high definition.
• Right click on an Image to perform a Reverse Image search.
• Right click after selecting a plain text URL to open as link.
• Double click on a plain text link to open URL in a new tab.
• Click icon (next to Menu) for a Cached version or Translation.
• Select some Website text, click Ctrl+Alt (Opt) for Translation.
• Ability to change/spoof the browser 'User Agent' when needed.
• Right-Click while holding Ctrl+Alt to remove a page element.
• History Navigation: Hold Right Mouse button, swipe left/right.
• Customize where new tabs open, and tab order when they close.
• Basic cookie management allows for export, import and wipes.

Security permissions that should be enabled for all the features:

"Allow access to file URLs" is required if opening local files as new tabs.
"Allow in private mode" has to be checked in order to work in incognito.
"Allow access to search pages" needed for search engine result pages.

For Chrome, Firefox, Brave, Opera, Vivaldi, and Edge (Chromium) browsers.