Hooke's Law, elasticity: http://webphysics.davidson.edu/Applets/animator4/demo_hook.html

Pendulum vectors: http://www.walter-fendt.de/ph14e/pendulum.htm

Pendulum 2: http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=11

Mass on  spring: http://www.walter-fendt.de/ph14e/springpendulum.htm

Mass on spring2: http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=148

mass on spring energy levels: http://phet.colorado.edu/en/simulation/mass-spring-lab

Longitudinal/transverse animation: http://paws.kettering.edu/~drussell/Demos/waves/wavemotion.html

Standing waves/beats (animation): http://paws.kettering.edu/~drussell/Demos/superposition/superposition.html

Reflection boundary conditions (animation): http://paws.kettering.edu/~drussell/Demos/reflect/reflect.html

standing waves: http://www.walter-fendt.de/ph14e/stwaverefl.htm

longitudinal standing wave: http://www.walter-fendt.de/ph14e/stlwaves.htm

spring driver resonance: http://www.walter-fendt.de/ph14e/resonance.htm

The virtual Ripple tank : http://www.falstad.com/ripple/

Phet Fourier: http://phet.colorado.edu/en/simulation/fourier

Fourier Synthesizer: http://www.falstad.com/fourier/

string harmonics: http://www.falstad.com/loadedstring/

Vowel synthesizer: http://www.falstad.com/vowel/

Sound source interference: http://www.falstad.com/interference/

Refraction of sound waves (animation): http://paws.kettering.edu/~drussell/Demos/refract/refract.html

Doppler/shock wave animation (with links to F-14 pix):