“OldSkoolVerb is a freeware algorithmic reverberation AU and VST plugin for professional music production applications. This plugin implements a kind of “classic” stereo reverb algorithm which is technically simple yet optimal. It also produces a very clear spatial image that blends well with the mix.
OldSkoolVerb offers you a comprehensive set of parameters permitting you to achieve various reverbs ranging from plate reverb to room reverb to hall reverb sound. OldSkoolVerb is best suited for non-percussive and soft-attack sounds like vocals, piano and pad sounds.”

(Image credit: Future) Mac/PC VST/AU/AAX £149. FabFilter’s reverb contender puts ease of use at the top of the agenda, with just six controls (plus dry/wet mix) governing a host of under-the-hood processes, including smoothly interpolated transitioning through “over a dozen” algorithms with the Space knob, which also sets the decay time from 0.2-10s, scalable from 0.1-20s with the. Size 12.1 MB / 11.7 MB / 18.3 MB OrilRiver is an algorithmic reverb that simulates the reverberation of a small room and great hall. OrilRiver has a classic parameters such as Damping, Stereo width, Pre-delay, Room size, Diffusion and a parameter as Damping intensity which allows you to change the reverb decay.
Tooltips in vst plugins flicker. Source : voxengo.com