・Password Manager & Two-factor Authentication (2FA)
Bitwarden
https://addons.mozilla.org/ja/firefox/addon/bitwarden-password-manager/
2FAS - Two factor authentication
https://addons.mozilla.org/ja/firefox/addon/2fas-two-factor-authentication/

・Bookmarks Management & Sync
xBrowserSync
https://addons.mozilla.org/ja/firefox/addon/xbs/

・Translation
TWP - Translate Web Pages
https://addons.mozilla.org/ja/firefox/addon/traduzir-paginas-web/
Simple Translate
https://addons.mozilla.org/ja/firefox/addon/simple-translate/
DeepL Translate: Reading & writing translator
https://addons.mozilla.org/ja/firefox/addon/deepl-translate/

・Download
DownThemAll!
https://addons.mozilla.org/ja/firefox/addon/downthemall/
Link Gopher
https://addons.mozilla.org/ja/firefox/addon/link-gopher/
IDM Integration Module
https://addons.mozilla.org/ja/firefox/addon/tonec-idm-integration-module
MyJDownloader Browser Extension
https://my.jdownloader.org/apps/
FileCR-Assistant.xpi
https://static.filecr.com/FileCR-Assistant.xpi