Avant Browser is a web browser that almost matches the features of Firefox.
iRider is supposed to be a fast and multi-page web browser.
Maxthon is a powerful tabbed browser.
Flock is a fairly well known browser built from Mozilla Firefox. This browser is said to be the most appropriate web browser for bloggers and social networking addicts.
Konqueror is an Open Source web browser.
Lunascape - The world’s first triple engine browser that supports IE for the Trident Platform, Firefox for Gecko and Chrome for WebKit.
Runecats Explorer Zeox is also a tabbed web browser.
Source: Daily Bits.