What do you mean by “modulation” in the context of “reverberation”?
I don’t see “modulation” being a feature of “CloudReverb”, or am I missing something?
There are some Nyquist reverb effects in this thread: https://forum.audacityteam.org/t/stereo-reverb/20310/1
And some more links:
https://forum.audacityteam.org/t/nyquist-reverb-plugin/24420/10
https://forum.audacityteam.org/t/stereo-reverb/20310/1
https://forum.audacityteam.org/t/help-with-cathedral-reverb/26093/4
There may be some others - I only did a quick search of the forum.
This effect is a subtle reverb, designed to give “breadth” to the sound (artificial stereo): https://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Pseudo-Stereo
And a load of delay effects: https://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Delay_and_Reverb