#No Enumerable Extensions Addon that lets you hide your installed extensions and avoid being fingerprinted based on them

You should also:

• make sure accept-langage header is generic (intl.accept_languages = en-us, en);
• disable webrtc (media.peerconnection.enabled = false);
• disable webgl (webgl.disabled = true);
• disable/defuse canvas (extension CanvasBlocker);
• disable/defuse referer (extension Smart Referer);
• hide fonts listing.