Here are some of my favourites:
EQs:
Baxandall Simulation Equalizer / BasiQ - Very nice sounding 3 band EQ; more of a sweetening device rather than freq correction
Win, Mac / VST, AU / 32bit, 64bit
https://www.kuassa.com/products/basiq/
Code Red Free - 60s classic all tube British console inspired EQ and preamp; Waves Abbey Road REDD console like
Win, Mac / VST, AU / 32bit, 64bit
http://www.shatteredglassaudio.com/product.php?id=106
PTEq-X - Vintage passive program EQ; one of the best sounding
Win, Mac / VST, AU / 64bit
https://www.kvraudio.com/product/pteq-x-by-ignite-amps
Mellowmuse EQ1A - Super smooth analogue style EQ; very light on CPU
Win, Mac / VST, AU, RTAS, AAX / 32bit, 64bit
http://www.mellowmuse.com/EQ1A.html
Nova-67P - Parallel parametric EQ; also 5 band parallel dynamic EQ
Win, Mac / VST, AU / 32bit, 64bit
https://vladgsound.wordpress.com/downloads/
Reverbs:
DX Reverb Light - Great little reverb that’s true stereo; won’t affect stereo imaging
Win, Mac / VST, AU, SAWStudio / 32bit, 64bit
http://www.anwida.com/download.asp
Teufelsberg Reverb - Lush reverb from NSA Listening Tower Impulse Responses
Win, Mac, Linux / VST, AU / 32bit, 64bit
http://www.balancemastering.com/blog/balance-audio-tools-free-teufelsberg-reverb-plugin/
OrilRiver - Algorithmic reverb; also features console style 3 band wet EQ
Win, Mac / VST, AU(Wrapper) / 64bit
https://www.kvraudio.com/product/orilriver-by-denis-tihanov
u-He Protoverb - Room reflection simulator reverb; great randomizer
Windows, Mac, Linux / VST, AU, AAX / 64bit
https://www.u-he.com/cms/protoverb
Tal Reverb 4 - Modulated vintage reverb sound; very diffuse sounding with fast build-up
Win, Mac / VST, AU, AAX / 32bit, 64bit
https://tal-software.com/products/tal-reverb-4
Voxengo OldSkoolVerb - Algorithmic reverb that’s more “classic” in sound
Win, Mac / VST, AU / 32bit, 64bit
http://www.voxengo.com/product/oldskoolverb/
Imaging:
A1 Stereo Control - Stereo width expander, has safe bass feature which centers freqs below an certain value
Win, Mac / VST, RTAS, AAX, AU / 32bit, 64bit
http://www.alexhilton.net/A1AUDIO/index.php/downloads
Panagement FE - Binaural panner and distance fader
Win, Mac / VST, AU / 32bit, 64bit
https://www.auburnsounds.com/products/Panagement.html
Misc:
A1 Trigger Gate - Gate / Pattern Sequencer, has random feature.
Win, Mac / VST, RTAS, AAX, AU / 32bit, 64bit
http://www.alexhilton.net/A1AUDIO/index.php/downloads
Audiothing Filterjam - Multi-band resonant filter with randomizer
Win, Mac / VST, AU, AAX / 32bit, 64bit
https://www.audiothing.net/effects/filterjam/
Klanghelm IVGI - From dirty track distortion to soft and subtle master bus saturation; can alter the symmetry of the signal without affecting the harmonic content much
Win, Mac / VST, AU, AAX / 64bit
https://klanghelm.com/contents/products/IVGI/IVGI.php
Audio Assault Transient - envelope shaper; has 2x switch
Win, Mac / VST, AU, RTAS / 32bit, 64bit
http://www.vst4free.com/free_vst.php?plugin=Transient&id=2153
Valhalla Freq Echo - from subtle choruses to the smokiest dubs
Win, Mac / VST, AU / 64bit
https://valhalladsp.com/shop/delay/valhalla-freq-echo/