Valhalla Space Modulator

Valhalla Space Modulator is a versatile modulation effect plugin.
Eleven algorithms allow you to get through-zero flanging, barberpole flanging, detuning, doubling, strange echoes, reverbs, and all sorts of effects that defy description.

https://valhalladsp.com/shop/modulation/valhalla-space-modulator/

PhatNoise Flanger

PhatNoise 

Flanger, Delay, Phaser, Lo-Fi Bass Filter, ModFilter

https://www.edinburghrecords.com/product-category/vst-plugins/

Dead Duck Free Effects Bundle

The Effects Bundle provides 24 original VST audio effect plugins covering everything from essential mixing tools such as EQ, compression and limiting to creative sound shaping tools such as delays, modulation effects and reverb:

• AutoFilter.
• AutoPan.
• BitCrusher.
• Channel.
• Chorus.
• Compressor.
• DeEsser.
• Delay.
• DualFilter.
• Equaliser.
• Expander.
• Filter.
• Flanger.
• Gate.
• Limiter.
• MonoDelay.
• Overdrive.
• Phaser.
• Reverb.
• RingMod.
• SigGen.
• TiltEQ.
• Tremolo.
• Utility.

http://deadducksoftware.blogspot.com.es

Synthscience

no more website...

http://www.vst4free.com/index.php?dev=Synthescience

HY-ChoFla

HY-ChoFla. This is a Chorus and Flanger combo free plugin and with chorus and flanging being such similar effects it is quite understandable that HY-plugins decided to release these in one package. Both modes of the plugins come with an HP/LP filter an LFO for modulation and a dry wet section on the output to either make the effect more pronounced or more subtle to taste.

http://hyakken.moo.jp/WordPress/product/hy-chofla/

Svep

Klevgränd Produktion
Svep kind of blurs the lines between a chorus effect, a phaser and a flanger. It can do all three of these effect types, as well as some more extreme (or really subtle) pitch modulation effects. The user interface is quite possibly the best part of Svep. It looks super stripped-down and simple, yet at the same time it doesn’t make you feel like you would need access to any additional control parameters. Using such a practical and well designed minimalist user interface is quite refreshing if you’re used to working with complex effects or virtual instruments.

http://klevgrand.se/products/svep/

rf Destroyer

rf Destroyer is a free multi-FX VST plugin. With multiple effect units in one page. Destroyer is useful for sound design and shaping the sound into something more exciting.

Effect units:
- Noise gate
- Drive and Distortion
- Bit crusher
- Pre and master filters
- Equalizer
- Compressor and Limiter
- Flanger and Chorus
- Delays and Reverb

http://rfmusic.net/en/vst_view.php?id=5