Free VST FM Synthesizers:

• Dexed by Digital Suburban

Dexed is a multi-platform, multi format plugin synth that is closely modeled on the Yamaha DX7. Under the hood it uses music-synthesizer-for-android for the synth engine and JUCE as a plugin wrapper. (Linux, Mac, Windows)

• Oxe FM by Oxe Music Software

Oxe FM Synth is a Multitimbral open source VST 2.4 instrument plugin for Windows, Linux and Mac OS X.(Windows)

• Stochaton by Eigentone Research

Here’s a crazy 8 oscillator hybrid digital synthesizer with a flexible modulation capabilities. (Mac)

• Uno FM by XSynth

Listed as one of the best Freeware FM synths around by Computer Music Magazine (Windows)

• VOPM by Sam

VOPM is an emulation of the Yamaha YM2151 (OPM) 4 operator FM sound chip. (Linux, Mac, Windows)

Free VST Subtractive Synthesizers:

• Abakos by HERCs Music Systems

Abakos is a free 2 osc analog synth plug-in developed by HERCs Music Systems. (Windows)

• ASynth by Antti@Smartelectronix

ASynth is a six voice virtual analog synthesizer featuring two oscillators and three circuit modelled filters. (Windows)

• Atlantis by Jeremy Evers

Atlantis is a unique synthesizer VSTi. It has nearly unlimited possibilities for creating new and exciting sounds! (Windows)

• Automat by Alphakanal

A virtual analog Audio Units (AU) synthesizer plugin that features a polyphonic stereo subtractive AltiVec/SSE optimized DSP engine with a flexible modulation patchbay. (Mac)

• BrainStormer by Roazhon DSP

BrainStormer is a freeware virtual analog synthesizer. (Windows)

• Charlatan by Dominique Wurtz

Charlatan is a polyphonic, subtractive virtual analog (VA) synthesizer plugin with focus on sound quality and easy usability. (Windows)

• Crystal by Green Oak

Crystal is a semi-modular software synthesizer featuring both subtractive synthesis and frequency modulation (FM) synthesis. (Mac, Windows)

• Daedalus by Northernbeat Audio

Daedalus, a free (donationware) polyphonic synthesizer VST instrument for Windows with special attention paid to MIDI controls such as Pitch Bend, Modulation Wheel, Velocity and Aftertouch. (Windows)

• MauSynth by Pekka Kauppila

MauSynth is a polyphonic analog-modeling subtractive synthesizer VST plugin by Pekka Kauppila. You can create all sorts of awesome sounds with it. (Windows)

• Nitrox by Sonic Lion

Nitrox is an analog type syntheziser with three oscillators, two stereo filters and a fully equipped stereo effects bank. (Windows)

• polyIblit by Andreas Ersson

3 oscillators per voice (Generated using BLITs (Band Limited Impulse Train) which gives oscillators with very low aliasing). (Windows)

• SuperWave P8 by SuperWave

If you’re looking for great leads, pads and strings, then check out this beast of a synth. (Windows)

• TAL-NoiseMaker by Togu Audio Line

TAL-NoiseMaker is an improved version of TAL-Elek7ro and has a completely new synth engine and a lot of improvements in sound and usability. The synth also includes a small effect section with a reverb, chorus and a simple bit crusher effect. (Linux, Mac, Windows)

• TAL-U-No-62 by Togu Audio Line

The U-NO-60 vst plugin is a polyphonic virtual analogue synth with a unique filter sound. An original JUNO 60 is used as reference for the oscillators and filters. (Mac, Windows)

• The blooo by Full Bucket Music

The blooo is a VST™2.4 polyphonic software synthesizer plug-in for Microsoft Windows® (both 32 and 64 bit) based on the classic subtractive synthesis architecture. (Windows)

• TS-Substance by Tactile Sounds

Substance is a virtual analog software synthesizer (VSTi) emphasizing simplicity, flexibility, and sound quality.(Windows)

• Tyrell N6 by Urs Heckmann

A low-cost HARDWARE analogue synth. (Mac, Windows)

• Voyager by Arguru Software

Voyager is a four oscillator subtractive synth. (Windows)

• Xhip by Aciddose

Xhip was originally designed as a basic synthesizer used inside a tracker (“acid tracker”) around 1999. Before that it had existed in pieces as small tools for generating samples to be used in more common trackers. (Windows)

• ZynAddSubFX by paulnasca

ZynAddSubFX is a fully featured open source software synthesizer capable of making a countless number of instruments. (Linux, Mac, Windows)

Free VST Drums:

• BIGROOMKIXSYNTH by Hinton & Fairchild

An all-round powerful electronic kick drum generator by Hinton & Fairchild (Windows)

• DigiDrum Pro by Audiosonic

DigiDrum Pro by Audiosonic is exactly what it sounds like it would be; a rock solid drum VST! (Windows)

• DreamDrums by Odo

It’s not a 606 or 808. But it can be pretty damn close to the 606 and 808. (Windows)

• EXD-80 by Third Harmonic Studios

The plugin is a virtual analog drum and percussion synthesizer with 128 User drum kit patches and comes with 16 preset drum kits. (Windows)

• TS-808 by Tactile Sounds

It’s exactly what you need in your life – a software emulation of the Roland TR-808. (Windows)

Free VST Pianos:

• 4Front R-Piano by George Yohng

This is a vintage piano module with a characteristic recognisable sound and a gentle overdrive. (Windows & Mac)

• Glue Reeds by Mokafix Audio

Glue Reeds is as simple plugin with almost zero controls, but with a great warm sound that you’ll learn to love.

• mda ePiano by mda@Smartelectronix

A decently clean piano VST with just the right amount of adjustments for the sound you want. (Windows)

• MrRay73 by GSi (Windows)

MrRay SeventyThree is a Rhodes Mark I emulation.

• MrTramp2 by GSi (Windows & Mac)

MrTramp2 is the sequel of GSi’s previous plugin “MrTramp”, a physical modeling simulation of the soulful Wurlitzer(TM) 200A Electric Piano.

Free VST String Machienes:

• Nabla by Full Bucket Music

The Nabla is a VST™2.4 software instrument for Microsoft Windows® simulating the KORG Delta DL-50 Strings Synthesizer from 1979 (Windows)

• S3 by Krakli

Designed to emulate the compliment StringZ2, S3 is unashamedly synthetic, with loads of modulation and movement in the sound. (Windows)

• StringSynth by AlgoMusic

Emulation (no samples here!) of those string synthesizers of the late 70’s made famous by ARP and Solina. It features a full ADSR envelope generator, a small effect section with a phaser, a delay and of course the ‘ensemble’ effect. (Windows)

• The deputy Mark II by Full Bucket Music

The deputy Mark II is a VST™2.4 software instrument for Microsoft Windows® (both 32 and 64 bit) in the tradition of classic string machines and early “polyphonic” synthesizers, written in native C++ code for high performance. (Windows)