VB cable

VB-Audio CABLE is a Windows Audio Driver working as Virtual Audio Cable.

http://vb-audio.pagesperso-orange.fr/Cable/index.htm

Polyphone

Soundfont editor

Polyphone is a free software for editing soundfonts in format sf2. These files contain a multitude of audio samples put together and configured so as to form musical instruments that can be used by synthesizers such as fluidsynth and played using a MIDI keyboard.

The goal of Polyphone is to provide:
a simple and efficient interface for creating and editing .sf2 files, available on Windows, Mac OS X and Linux,
tools to facilitate and automate the editing of different parameters, making it possible to handle a large amount of data.

http://polyphone.fr/

Ring Modulator

MUSICALLY USEFUL RING MODULATOR?
Yes. The RM 101 is a re-creation of a classic effects chain using a vintage ring modulator. However, unless you are handy with a soldering iron, have access to an old transistor ring modulator, an old dual channel tube amp, an old tube echo unit, a 2-pole ladder filter, and an old chorus/flanger pedal, you will not have much luck capturing the tone of the RM 101.

http://www.vstplugin-sonicxtc.com/freebies

Scalefreq Generator

Scalefreq Generator is a tool for rendering frequencies of notes / musical scales into various output formats. It’s primarily aimed for mixing/mastering engineers and other musical interested people. The frequencies of musical scale or non-scale notes (inverse) are important in mixing and mastering situations. E.g. non-scale frequencies are often attenuated using an EQ.

Scalefreq consists of a core system, a render-plugin architecture and a graphical frontend for convenient user interaction.

http://blog.airmann.de/scalefreq-generator-v1-0/

Pitchd

PITCHD is a delay plugin with a pitch-shifter in the delay path.

Pitch shift amount can be adjusted in semitones or fine. Delay can be set in milliseconds or host synced. Can be used as send or insert effect.

Let the echo’s pitch drift away softly with a slight detune or up or down by a maximum of one octave to create strange effects.

http://music.service-1.de/html/wok_free_vst_plugin_pitch_shif.html

Fracture

GlitchMachines Fracture

Fracture features a buffer effect, a multimode filter, three LFOs and a delay. This plugin is geared toward adding glitchy articulations and abstract textures to your projects. Use it on anything from drum and percussion loops to synth lines and sound effects. Fracture’s intuitive interface and diverse features make it simple to give your projects a unique technical edge.
http://www.glitchmachines.com/downloads/fracture/

retro boy

Retro Boy is a virtual analog chiptune synth/emulator. Chiptune or otherwise known as 8-bit music is music or sounds synthesized by the sound chip of computers, video game systems, and most handled gaming systems. Retro Boy features a single oscillator that has seven waveshapes: 12.5% pulse, 25% pulse, %50 pulse, saw, triangle, sine, and noise.

http://www.sbaudio.org/retro-boy

futucraft kairatune

Kairatune is designed to produce crisp and tight electric sounds for electronic music production

Kairatune is not your all-in-one synthesizer. It's designed and engineered to be as powerful and versatile as possible in it's target role as your source for tight bass, unique lead and shiny SFX sounds.

http://futucraft.com/category/kairatune/

OBXD – Oberheim OB-X Emulation

https://obxd.wordpress.com/

about:
http://bedroomproducersblog.com/2014/01/22/obxd-vst/

download:
http://www.kvraudio.com/forum/viewtopic.php?f=1&t=387568

VSTForx

(not free... a 4 plugin demo avalaible)

VSTForx is a full-modular effect network creation tool which comes as a VST-plugin. With VSTForx you are able to load any number of VST-plugins and connect them anyway you want.
Additional modules allow you to manipulate such signal chains and offer a whole new way in mixing and producing.

http://www.vstforx.de/

Luxonix multi-fx

LFX-1310 is a Free plug-in multi-effector including 24 types of algorithm and 3 serial slots. This freeware is the stand-alone version of Effecting Module of Ravity-S & Ravity-R.

Including 24 Effectors

- S'Filter 12 / S'Filter 24 / 3-band EQ
- Peak Compressor / RMS Compressor
- Overdrive / Distortion / Amp Distortion
- Crusher / LP Noise / Stereo Image
- Chorus / Flanger / Phaser / Auto Wah / Tremolo / Auto Pan
- Delay / Stereo Delay / Ping-pong Delay
- Gate Reverb / Room Reverb / Hall Reverb / Spring Reverb

http://www.luxonix.com/lfx.html

LeftOver Lasagne

Pushtec 5+1A is a 6-band mid-range and program EQ, it contains a decent amount of presets and PDF manual in multiple languages. A Winamp plugin version is also included. The algorithm behind the stunning user interface is based on a circuit schematic of one (well, two to be exact) of the most sought-after vintage analog EQs. We combined a superb program EQ with a rare midrange EQ to end up with a very flexible all-around tool for your mixing and mastering sessions.

http://www.leftoverlasagne.com/leftoverlasagne/index.html

TriDirt

Distortion
http://web.archive.org/web/20041009155611/http://www.noizware.com/software.htm