Fedora (and Ubuntu) Linux users looking for more screensavers should install the package xscreensaver-gl-extra via their favorite package manager:

Fedora

Use yumex, or via command line:
sudo yum install xscreensaver-gl-extra

Ubuntu

Use Synaptic, or via command line:
sudo apt-get install xscreensaver-gl-extra

Here’s the package description:

This package contains the rest of the 3D (OpenGL) screen saver
modules from the xscreensaver collection. This package is used
by both xscreensaver and gnome-screensaver.

This is the set of GL screensavers not shipped by default with
xscreensaver-gl: antinspect, gleidescope, glknots, atunnel, blinkbox,
bubble3d, circuit, cubestorm, glsnake, jigglypuff, lavalite, lockward,
mirrorblog, moebius, boebiusgears, molecule, morph3d, pipes, polyhedra,
polytopes, pulsar, queens, sierpinski3d, spheremonics, stonerview,
superquadrics, topblock, voronoi endgame, engine, flipflop, flipscreen3d,
flurry, flyingtoasters, gears, gflux, antmaze, atlantis, blocktube, boing,
bouncingcow, boxed, cage, carousel, crackberg, cube21, cubenetic, dangerball,
extrusion, fliptext, glforestfire, glhanoi, glplanet, juggler3d, klein, lament,
menger, noof, pinion, providence, rubik, sballs, sproingies, staris, starwars,
tangram, timetunnel.