I'm compiling a list of good VST plugins that have native Linux support if anyone is interested.

Instruments -

Vital (wavetable synth)
Helm (wavetable synth)
Surge XT (wavetable synth)
Odin 2 (hybrid synth)
Dexed (FM synth)
Tyrell Nexus 6 (analog synth)
Podolski (Apreggiator/Step Sequencer)
Vaporizer 2 (wavetable synth, you have to compile from source)
Zyn-Fusion, zynaddsubfx (synth)
Amigo 2.0 (sampler, chopper)
All Togu Audio Line plugins (TAL)
Zebralette/Zebra 2 (synth)
Hyslicer 2 (sampler, chopper)
Rave Generator 2 (rompler)
Sitala (drum sampler)
Speedrum 2 and Speedrum Lite (insane sampler)
Nils K1 (Kawai K1 clone)
Cardinal Modular Synth

Effects -

fircomp2 (compressor)
Rough Rider 3 (compressor)
All Togu Audio effects plugins
TLS 1295 LEA vintage compressor
Bertom Phantom Center (Stereo Imager)
Surge XT effects
All plugins by Superflydsp
All plugins by Chowdhury DSP
Cardinal Modular Synth (effects)
All plugins by GVST (http://www.gvst.co.uk/)
Transperc (transient shaper)
Inner Pitch FE (pitch shifter)
Lens (spectral dynamics processor)
Renegate free
Basic Limiter (brickwall limiter)
Tonelib Noise Reducer (denoiser/gate)
Room Reverb

More will be added in the future, I will pin this post to my profile. If you need links to any of these let me know.