Here are some other programs worth looking at:

 AmigaXv: Is a quite decent (some say great..) image manipulation program
that supports GIF, JPEG, TIFF, PBM, PGM, PPM, X11 bitmap, RLE, PDS/VICAR,
Sun Rasterfile, BMP, PCX, IRIS RGB, XPM, Targa, XWD, PostScript, PhotoCD and PM.
A several image operators is also available. The program can be found on aminet
as AmigaXv210.lha in gfx/edit. Not much support for this program so I will be
surprised if a newer version should show up..(Interpret as: sporadic improvements,
no new aminet versions..)

  Fractint : THE fractal program. 'nothing compares 2 U'..
It can render a stunning amount of different fractal types
and also do some nice 3d effects. If you are looking for a
mandelbrot/julia only program there are probably other programs
out there, but if you want more, this one is it! It is available
on aminet in gfx/fract as fractint26.lha. fzoom.lha is a program that
will generate a script file for use with fractint to make fractint create
fractal animations. Not much support for this program either, but a version
of the latest pc version (19) has been made.

  XAnim: A great program by Mark Podlipec for viewing a huge number of different
animation formats among them Quicktime, AVI, FLI/FLC, IFF and then some..
My port of xanim is available on aminet as xanim8.lha in gfx/show.

 Xmgr: The best dataplotting manipulation tool around (fairly objective statement..)
 + Polynomial regression, splines, running averages, DFT/FFT, cross/auto-correlation.
 + Plots up to 10 graphs with 30 datasets per graph.
 + User-defined scaling, tick marks, labels,  symbols, line styles, colors.
 + Batch mode for unattended plotting.
 + Read and write parameters used during a session.
 + Support through device independent graphic drivers for PostScript, 
   and FrameMaker .mif format.
It's available on aminet as xmgr2.lha in misc/sci.

 Xfig: A nice structured drawing program.
 "Xfig can produce output in several different formats: Encapsulated PostScript, 
IBM-GL (HP/GL), Pic, PiCTeX, LaTeX, box, epic, eepic, eepicemu, textyl, tpic, X11 Bitmap,
X11 Pixmap and gif." Look for xfig4.lha on aminet.

Smaller programs include: 
xconq: a war strategy game.
xasteroids: an asteroids type of game.
xdaliclock: a 'morphing' clock.
xspringies: A spring simulation system.

TP