Ok this one isn’t really a surprise.. Combining a spectrum analyzer, a correlation meter, a level meter and more, SPAN by Voxengo is probably the most recommended free plugin out there, and a must have for any music producer or musician !

Whether it be for sound design or mixing, an oscilloscope is a very useful monitoring tool: From observing how a compressor shape transients to checking low frequencies phases interactions, this freeware by Smart Electronix will get you covered.

Managing your sample pool can be tedious: This free plugin by ADSR aims to help you in this task by providing an all-in-one solution for organizing, searching and browsing the indexed sample content.

Keep an eye on the time spent on your project with ProjectTime by HOFA: It runs as long as your project is loaded, can be paused when needed and can generate a commented log.

This neat little plugin guesses chord names based on MIDI input or clicked notes: Although the developer seems inactive, luckily this plugin is open source and can still be found out there.

Both developed by MAAT, 2BusControl is a universal L/R or Mono/Diff monitor control that also features a correlation meter, while GON is a free goniometer that replicates an analog oscilloscope with a simple and straightforward visual interface.

If you mix with headphones and ever wondered how you mix will sound in a different environment like your car, a recording studio, a big venue or a 5.1 surround speaker system, just throw this plugin by Beyerdynamic on your master and check it out !

Ginger Audio’s Virtual Audio Driver isn’t a plugin, but more a utility tool that can pass any audio signal to other applications without any latency: Useful for streamers, engineers, podcasters, educators
Unfortunately it’s currently available for Mac only…

Youlean Loudness Meter 2 is an advanced and feature-rich tool for measuring loudness levels in audio content. This plugin provides comprehensive loudness metering, ensuring compliance with industry standards such as LUFS. Its user-friendly interface and detailed visualizations offer invaluable insights into loudness levels, making it essential for mastering and ensuring audio content meets professional standards.

Plugin Uninstaller by Wide Blue Sound is a convenient tool specifically crafted to efficiently remove plugins from your Mac. It ensures a thorough and hassle-free removal process, aiding in the maintenance of a clean and organized plugin library. Featuring a user-friendly interface and straightforward functionality, it simplifies the task of managing and uninstalling plugins on your Mac, effectively streamlining your workflow.

Despite its somewhat unattractive interface, this free plugin by Bertom Audio accurately analyzes and displays frequency responses. It operates through two instances: one generates a signal, while the other, with the plugin in between, analyzes it. Perfect for precisely measuring the impact of effects or equalizers.

MVMeter2 by TB Pro Audio is a free VU meter plugin that features various modes and an adjustable 0dB level. It provides accurate metering for levels and stereo details, assisting in efficient audio signal monitoring and adjustments. Its user-friendly, resizable, and customizable interface makes MVMeter2 an invaluable tool for maintaining ideal audio balance, gain staging, and stereo imaging.

Process.Audio has released Protility, a free all-in-one utility plugin for Mac & Windows:
Designed as a mix prep tool, Protility helps refine tracks before EQ and compression by offering phase correction, bass mono conversion, stereo width control, gain trim, metering, and more. Ideal for improving clarity and balance, it’s a great first insert in your mix chain.
With a clean, modern UI and preset management, it’s a simple yet powerful tool to streamline your workflow.

OccularScope by Bom Shanka Machines is a free audio visualizer plugin that synchronizes visual representations with audio, enabling real-time sound analysis. Featuring a distinct interface and dynamic visualizations, OccularScope presents an engaging way to explore audio, suitable for music production setups or enhancing kick/bass interaction.

Fire The Gold by Acustica Audio is an analog-inspired preamp plugin designed to infuse audio with warmth and character. It emulates the sonic qualities of a vintage preamp, providing rich saturation and harmonics. Featuring an intuitive interface and advanced oversampling, it enriches audio depth while preserving sound quality, even under heavy usage.

Soundly‘s Place it is a free convolution plugin that mimics different speakers and spaces, providing a ‘wall filter’ for inventive audio design. It accurately reproduces playback devices and room acoustics, enabling a range of diverse sound experiences.

MFreeForm Phase is a versatile plugin by Melda Production designed for precise phase manipulation in audio. It provides control over phase shifts and innovative tools for adjusting stereo images, enhancing audio depth and spatial perception. This plugin offers a comprehensive solution for shaping and refining phase characteristics in audio production.

Prism by TDR is a new, modern and free frequency analyzer designed for easy use, offering precise insight into spectral properties while focusing on human audio perception. It provides advanced features that are currently offered only by paid plugins.