TabFreezer by adam2am

TabFreezer is a lightweight Firefox tab suspender focused on real day to day memory savings

It is a fork of Tab Suspender with two key improvements:
- Freeze pinned tabs on startup so heavy pinned tabs do not immediately consume memory when Firefox opens.
- Discard all tabs now with a keyboard shortcut for instant cleanup without opening the popup.

This is especially useful if you keep many pinned tabs for work, research, chat, dashboards, or media sites. In real use, a large pinned-tab setup can consume huge amounts of RAM at startup. For example, a session that opens around 15 GB with tons of pinned tabs of memory usage can drop closer to 1 GB after startup when pinned tabs are unloaded until needed

Key features:
- Automatically freezes inactive tabs after a configurable delay
- Optional protection for audible tabs
- Optional protection for pinned tabs during normal browsing
- Unload pinned tabs on browser/window startup
- Discard all tabs now button and keyboard shortcut
- Per-tab “do not suspend” toggle
- URL host whitelist
- Simple local settings, no accounts, no telemetry, no cloud service