Just 4 fun the Tweakbench VST Collection updated on October 24, 2006.
Some still available to the public, also includes several rare plugins!

39 Synths & FX to indulge in:

TB.VSTi.Instruments - Directory Structure:
- TB.Bentside.v1.04.VSTi (sampled strings) (RARE)
- TB.Carillon.v1.1.VSTi (chimes synthesizer)
- TB.Comma8.v1.0.VSTi (retro and chip type sound synthesizer) (RARE)
- TB.Dimate.v1.02.VSTi (synth) (RARE)
- TB.Dropout.v2.2.VSTi (granular sample cycler)
- TB.Field.v1.2.VSTi (ambience tool)
- TB.Herzog.v1.0.VSTi (strategy synthesizer gameTable synthesis) (RARE)
- TB.Lilypad.v1.0.VSTi (layered pad synthesizer) (RARE)
- TB.Linus.v1.0.VSTi (FM sound effects synthesizer) (RARE)
- TB.Minerva.v1.1.VSTi (granular percussion)
- TB.Monomate.v2.2.VSTi (analog synthesizer)
- TB.Padawan.v1.1.VSTi (pad synthesizer)
- TB.Papaya.v1.1.VSTi (mallet synthesizer)
- TB.Peach.v1.2.VSTi (nes synthesizer)
- TB.Pippo.v1.2.VSTi (string synthesizer)
- TB.Pressure.v1.1.VSTi (heavy synthesizer) (RARE)
- TB.Rebar.v1.3.VSTi (step synthesizer)
- TB.Ritual.v1.0.VSTi (bass synthesizer)
- TB.Rotovier.v1.0.VSTi (analog array synthesizer) (RARE)
- TB.Shinobi.VSTi (shinobi ninja synthesizer) (RARE)
- TB.Shoryuken.VSTi (phase distortion synthesizer) (RARE)
- TB.Tango.VSTi (visualization synthesizer) (RARE)
- TB.Tapeworm.v2.0.VSTi (mellotron emulation synthesizer)
- TB.Toad.v1.2.VSTi (nes drum synthesizer)
- TB.Triforce.v1.6.VSTi (nes synthesizer)
- TB.Trimate.v1.02.VSTi (sidchip emulation synthesizer) (RARE)

TB.VST.Effects - Directory Structure:
- TB.Breakdown.v2.2.VST (filter cycler)
- TB.Cairo.v1.3.VST (tempo gate)
- TB.Defend.v1.0.VST (multi-fx module)(RARE)
- TB.Effexor.v1.0.VST (mutli-effect processor) (RARE)
- TB.Grumblebum.v2.6.VST (fx processor)
- TB.Maelcum.v1.1.VST (tape delay)
- TB.Mashup.v2.2.VST (delay cycler)
- TB.Pudding.v1.2.VST (granular delay)
- TB.Shap0r.v1.0.VST (waveshaping effect processor) (RARE)
- TB.Sideslip.v2.2.VST (granular cycler)
- TB.Sniper.VST (stereo scope and frequency analyzer) (RARE)
- TB.Solstice.v1.0.VST (fx module) (RARE)
- TB.Yoink.v1.2.VST (inline sample tool)

More info
http://www.tweakbench.com/