Graphing & Plotting

Plots
Graphs
LabPlot
AlphaPlot
Gephi
Veusz
SSPlot
Logarithm Plotter
Squey
ROOT
Funkcio
Gwyddion
Makhber
Fityk
Kst
Rocs
mMass
Linien

Electronics

QElectroTech
GElectrical
Color Code
QSpeakers
Xnec2c
Hopsan
Lightwave Explorer

Medical

Aliza MS
InVesalius

Math

Qalculate
KAlgebra
Calculus
wxMaxima
Genius
Setzer
KBibTeX
Cantor
Climaxima

Chemistry

Kalzium
Avogadro
Python Molecular Graphics
BKChem
Molsketch

Maps & Astrology

KStars
Marble
Gaia Sky
Viking
OrbVis
ParaView
SUMO
OSM Scout Server
Astronum