Giant Verb is a free reverb plugin designed for infinite spaces. Its total feedback can go up to 100%, which means an infinite decay time. Other features are the analog input behavior (pre-warmth factor) and reverb modulation for smooth and discrete chorusing.
The interface is direct and intuitive, optimized for sound over technical stuff.
Giant Verb is available in VST & AU plugin formats for Windows and macOS. There’s an issue at the moment with the plugin loaded in FL Studio 20.1.2 (Windows 64 bit), more precisely its UI crashes.
You can download it for free at Digital Systemic Emulations – no registration required.
More information: Digital Systemic Emulations