Safest Volume Booster от Gaurav Patidar

Volume Booster gives you a simple popup for increasing audio and video volume above the normal browser limit.

Use the slider to raise volume from 100% up to 600%, choose a quick preset, disable boosting with one toggle, or reset everything back to the default level.

Features:

• Boost audio/video volume from 100% to 600%
• Quick preset buttons for 100%, 200%, 400%, and 600%
• Popup toggle to enable or disable boosting
• Reset button for returning to normal volume
• Works through a content script on pages with standard audio or video elements

Privacy: This extension stores only your local volume preference and enabled/disabled state in browser extension storage. It does not collect, transmit, sell, or share user data. It does not use analytics, tracking scripts, external API calls, or remote code.

Open source: GitHub repository