[mhd]

I quite liked Arena and Chimera (the Xaw one, not the predecessor of Camino) in my early Linux days. Although Netscape 2/3 quickly took over.

[theoh]

That Chimera was pretty nice, all right:

http://freshmeat.sourceforge.net/projects/chimera-www

In a similar category, but using Gtk, was Ralph Levien's gzilla https://www.levien.com/gzilla/