Vital by Matt Tytel is a free and powerful spectral warping wavetable synthesizer with a well built and intuitive visual interface despite its complex possibilities: This might be a great starting point even if you’re new to sound synthesis.

A must have !

Gatelab by Audiomodern is a gate sequencer and volume modulation generator designed to add rythmic movement to static pads, drones, basslines & more.

You can customize the modulation sequence or use its randomize functions to create all sorts of unexpected riffs and patterns.

s(M)exoscope by Armando Montanez is a free oscilloscope that allows you to visually monitor audio waveforms:

This is a must to check the low frequencies phase interactions between your kick and bass for instance, and get a strong, consistent low end.

bx_subfilter by Brainworx is a free plugin designed to add clarity and definition to low-end:
by cleaning up the extreme low and help controlling the sub-bass while boosting a target frequency range.

There are various applications in which you can use it, including strengthening a bassline’s fundamental frequency based on its key.

With its 14 different modes, Supermassive by Valhalla is a must-have freeware designed to generate massive delays, lush reverbs and never-ending soundscapes:

Use it to create luscious clouds of reverb, otherworldly delays, and swelling waves of feedback unlike any you’ve heard before.

A1TriggerGate by Alex Hilton gate sequencer is a free plugin specifically designed to transform static audio signals and breath life into dull sounds.

DJM Filter by XFer Records plugin provides a Pioneer DJM filter emulation in a dual LOWPASS/HIGHPASS filter module – all in one slick control that sounds great and can easily be automated within your DAW.

Fracture by Glitchmachines is a versatile effects processor designed to add glitchy articulations and abstract textures to your sounds: Use it on anything from drums to synth lines or vocals for creative results.

Psyscope by FX23 is a free beat-synced oscilloscope designed for Windows, capable of analyzing up to four audio channels simultaneously. It provides options to stack, display individually, or layer waveforms in different colors.

While a paid version with valuable additional features is available, the free one is a already a must for monitoring kick bass interaction, overlap, and making phase adjustments.

OccularScope by Bom Shanka Machines is a free oscilloscope available for Mac and Windows:
It synchronizes visual representations with audio, providing real-time sound analysis.

Key features include beat or bar visual synchronization, side chain input for displaying multiple sources in one instance, adjustable delay compensation, a fully resizable graphical user interface (GUI), auto or manual gain control and more.

Freshly released few weeks ago, Geonkick by Iurie Nistor is a free alternative to Sonic Academy’s Kick2, specializing in designing kicks and percussion sounds.
Although it offers slightly fewer features than Kick2, Geonkick provides two oscillators and a noise generator, offering ample flexibility for kick design. Unfortunately, it is currently compatible only with Windows and Linux.

MFreeForm Phase by Melda Production is a versatile plugin designed for precise phase manipulation. It allows control over phase shifts and offers innovative tools for adjusting stereo images, enhancing audio depth, and improving spatial perception.
While it may appear a bit challenging for beginners, it shines as a free and comprehensive solution for shaping and refining phase characteristics in audio production.

Prism by TDR is a modern, free frequency analyzer featuring real-time frequency masking, peak/RMS smoothing, and more through upcoming updates.

Its elegant interface is fully resizable, supports fullscreen mode, and offers a fast, high-quality graphic display.

EpicCLOUDS by VOS is a robust reverb plugin that excels in producing clean, lush, and expansive ambient reverb textures reminiscent of ‘Supermassive,’ yet with improved clarity and a simplified interface.

The clean and straightforward user interface ensures easy operation, making it an excellent choice for adding luscious reverbs and spaces to your Psytrance productions.

JC-303 by Midilab is a fresh newcomer in the free plugins realm, aiming at reviving the iconic Roland TB-303 heard in countless electronic track, including Psytrance and Goa classics.

Compatible for Mac & Windows, it faithfully emulates the 303’s distinctive sound and mimics most of the original’s controls fairly well: It stands out as a nice and promising tool if you want to get a faithful 303 emulation for your productions.