Great Freeware / Donationware VST plugins (A work in progress)

This does not aim to be a complete list, rather it is a list of plugins that fit my definition of good and useful.

VST:
Eq / Filters:
Cockos - ReaEq: IIR based equalizer with unlimited bands, many types of filters (shelfs, bands, LPF, HPF, notch, bandpass, allpass) not to mention very good and precise editing.

Habib - Eq31: 31-band graphic equalizer, mono and stereo.

Habib - keFir: Zero latency FIR filter based on impulse responses from wave files. Simply put, this allows you to apply a recording of an effect or environment to a signal. Simulate your signal going through an amp/cabinet, a telephone, an old radio etc. The page has links to impulse responses you can use with it.

Voxengo - Overtone GEQ: 7-band harmonic (overtone) graphic equalizer with multi-channel support. Offers extensive internal channel routing capabilities, and supports mid/side channel processing. Beside equalizing, Overtone GEQ applies harmonic enhancement processing: it uses 7 harmonic enhancement modules, one for each EQ band. This generates a complex harmonic coloration you will probably like a lot.

Dynamics:
Cockos - ReaComp: Ultra-configurable compressor with soft knee support, sidechain filters, sidechain inputs and variable RMS size.

Cockos - ReaXcomp: Multi-band compressor with unlimited bands.
Controls per band: ratio, threshold, knee, attack, release, makeup, program dependent release, feedback detector and RMS size.

Cockos - ReaGate: Ultra-configurable gate with sidechain filters, sidechain input, lookahead for pre-open, hold control, hysteresis control and variable RMS size. Can send MIDI events on gate open/close. Also has Wet/dry mix and noise mix (can add noise when gate is open).

Digitalfishphones - Fish fillets: This magnificent trio of dynamics processors feature dead simple controls and a sound of their own.
The fillets are:
Blockfish, a vca/opto compressor with saturation and "air".
Floorfish, a gate/expander with adjustable frequency.
Spitfish is a de-esser.

Twisted Lemon - Sidekick v3: This sidechain ducking/keying compressor, allows you to do stereo sidechaining in pretty much any vst host via it's own intra-host routing system.

Delay / Echo:
Cockos - ReaDelay: Multi-tap delay with no practical limit on tap count and up to 10 second delay per tap.
Feedback, LPF/HPF, resolution reduction, stereo width and volume/pan per tap.

Togu Audio Line - Dub: A vintage style delay effect. It can be used for a wide range of delay effects from clean to extreme distorted, resonating never ending delays.
12dB resonance filter, low cut filter, maximal 4 Seconds delay time, limiter with distortion for rising feedbacks or loud inputs, delay time and feedback for each channel (linkable), input signal swap (L/R swap), filter feedback and filter fx mode (filter in feedback path or as post fx), filter mode for input (input signal will be filtered too) and easy to use midi learn. Yeah mon!

Voxengo - Tempo Delay: Delay module based on tempo, incorporating EQ and tremolo sections with separate controls for each output channel.

Reverb:
Magnus Jonsson - Ambience: In Magnus' own words, Ambience is a reverb that rivals the quality of the best commercial reverbs. I can't disagree with that, it really does sound very good. Two-band eq and damping, gating, very good presets and a nice clean gui.

Effects:
Habib - Extremist: Guitar multi-effect plugin.

Togu Audio Line - Chorus-60: A standalone version of the chorus implemented in U-NO-60.
Characteristics of the Juno-60 chorus, 2 modes, Dry/wet adjustable, Volume knob, Low CPU.

Togu Audio Line - Flanger: An easy to tweak stereo flanger effect with its own special sound and some asymmetric analog like components in the feedback corner. Useful for a wide range of flanger effects from subtle to extreme.

Togu Audio Line - Phaser: A carefully modelled stereo phaser effect. The user can choose between two, four and six stages. Its possible to adjust the lowest and highest frequency of the filter.

Saturate / Amp / Distortion:
Atom Splitter - Distroyr: Multi-algorithm plugin with lots of potential for getting just the edge your sound needed.
Algorithms: Feedback, signal clipping, bit crush, valve distortion, saturate and overdrive.

Togu Audio Line - Tube: A saturation plugin that has the characteristic of tubes and an additional amplifier mode. It's very suitable for adding higher harmonics and can give more excitement and analog character to digital sounds or drums.

Voxengo - Tube Amp: Add a tube-like warmness to any audio material.

Voxengo - Boogex: Guitar amplifier plug-in with a variety of sound shaping features. Achieve anything from a slight distortion to heavy distorted sound. Also has support for speaker cabinet impulse responses with a selection of built-in impulses is available

Mono / Stereo:
Voxengo - Stereo Touch: Add stereo width to audio tracks. Most effective on mono pad sounds and alike.

Voxengo - MSED: Mid/side encoder/decoder.

Utility:
Cockos - ReaFIR: FFT based dynamics processor (requires host plug-in delay compensation) with FFT sizes from 128 to 32768. Allround effect, with uses including Dynamics, EQ, Compression, Gate and Noise removal.

Cockos - ReaStream: Supports streaming from host to host of audio and/or MIDI over LAN, streaming from different host software on each end and UDP broadcast for streaming one to many.

Voxengo - Recorder: Allows you to record the output of the track or bus into a stereo WAV file of specified bit depth. Routing to MME soundcard is also supported.

Voxengo - Audio Delay: Delay stereo audio for a specified amount of milliseconds. Delay can be separately specified for each channel.

VSTI:
Andreas Ersson - ErsDrums: A ten-part virtual analog drum machine with seven different algorithms.

Andreas Ersson - Iblit: A monophonic virtual analog with BLIT (Band Limited Impulse Train) oscillators, which gives very low aliasing.

Andreas Ersson - Poly Iblit: The polyphonic version of Iblit.

Dash Signature - DaHornet: This classic mono synth has a nice dusty sound. I like to refer to it as "electro in a box". Get the serial number from the download page.