Biomer: online java applet, model builders for polynucleotides (DNA/RNA), polysaccharides and proteins, interactive molecule editor, AMBER force-field based geometry optimization, simulated annealing with molecular dynamics, and the ability to save gif, jpeg, and ppm images
GROMACS: fully automated topology builder for proteins, molecular dynamics, leap-frog integrator, position langevin dynamics, normal mode analysis, electrostatics, non-equilibrium MD, NMR refinement with NOE data, large number of powerful analysis tools, ...
Hückel: constructs the Hückel matrix, the programs then calculate, display
MOIL: molecular modeling, energy minimization and molecular dynamics simulation for biomolecules like proteins