Mozilla Firefox 25.0.1 Multilingual

Web browser without installation.
Portable Nightly MultiVersion 32-64 bit en-US Online (0.4 MB)
In first screen enter Version Number: 28.0a1
Portable Aurora MultiVersion Multilingual Online (0.4 MB)
Select language and enter Version Number:27.0a2
Portable Firefox MultiVersion Multilingual Online (0.4 MB)
Select language and enter Version Number: 26.0b10 or 25.0.1 or 24.1.1esr or 17.0.11esr or 3.6.28

Final and Beta use same launcher and profile but Aurora and Nightly have their own.
Results in Acid3 Test : 100 %

Optimized Firefox Browser without installation.
Portable Pale Moon 24.x 32-64 bit Multilingual Online (0.5 MB)
Select language and enter Version Number: 24.2.0
On first run, check allow Language Pack installation, click on Continue but close and restart by launcher.
Portable Pale Moon 3.6.x Multilingual Online (0.4 MB)
Select language and enter Version Number : 3.6.32

64-bit variant of Firefox without installation.
Download Portable Waterfox Multiversion en-US Online (0.4 MB)
In first screen enter Version Number: 24.0

PasswordFox 1.36 for Firefox Portable.
Download PasswordFox Multilingual Online (0.4 MB)
Extract and run PasswordFoxPortable.

Flash Plugin

Can use Java Runtime Environment Portable

Multilingual Online will download setup in selected language (Afrikaans, Shqip, عربي, Հայերեն, অসমীয়া, Euskara, Беларуская, বাংলা (বাংলাদেশ), Bosanski, Brezhoneg, Български, Català, 中文 (简体), 正體中文 (繁體), Hrvatski, Čeština, Dansk, Nederlands, English (British), English (South African), English (US), Esperanto, Eesti keel, suomi, Français, Frysk, Pulaar-Fulfulde, Gàidhlig, Galego, Deutsch, Ελληνικά, ગુજરાતી, עברית, हिन्दी (भारत), magyar, íslenska, Bahasa Indonesia, Gaeilge, Italiano, 日本語, ಕನ್ನಡ, Қазақ, ខ្មែរ, 한국어, Latviešu, lietuvių kalba, Македонски, മലയാളം, मराठी, Norsk bokmål, Norsk nynorsk, ଓଡ଼ିଆ, فارسی, Polski, Português (do Brasil), Português (Europeu), ਪੰਜਾਬੀ, română, Русский, Српски, slovenčina, Slovenščina, Español (de Argentina), Español (de Chile), Español (de México), Español (de España), Svenska, தமிழ், తెలుగు, ไทย, Türkçe, Українська, Tiếng Việt, Cymraeg, isiZulu) and extract files.
Extract and run FirefoxPortable or PaleMoonPortable (both have their own profile).
Settings of installed Firefox should be preserved.
Multi-Users: change Profile by editing FirefoxPortable.ini or PaleMoonPortable.ini with User=NameOfNewUser
Associated to Thunderbird Portable if FirefoxPortable and ThunderbirdPortable folders are in the same folder. A click on a mailto link in FirefoxPortable open a new mail in ThunderbirdPortable (don't work on Windows 8).